A good electric cell should have the following except

D. Cost and dangerous of the cell

A. A minimum of polarization effect

C. A cheap and safe electrolytes

D. Cost and dangerous of the cell

Body floats in fluid when its …………………

B. Displaces its own weight of the fluid

A. Displaces its own volume of the liquid (fluid)

B. Displaces its own weight of the fluid

C. Displace its own density of the fluid

D. Is no longer subjected to gravity

A member of the crew of a SPACESHIP experiences weightlessness in a space when they

A. Fall freely from the earth’s gravitational field

C. In between the sun and the earth

D. Holding anything in space is negative

A motor boy of a driver saw what seems to appear to be a pool of water a head of him, while his driver drives a new truck on a sunny day. Which of the following explains his observation?

D. The sun ray from the sky were passing from a hot air (layer) to cold layer

B. He must be thinking of water and food

C. He was seeing the shadow of the car

D. The sun ray from the sky were passing from a hot air (layer) to cold layer

Efficiency of a transformer is equal to

D. Efficiency of a transformer = (power developed in the secondary coil ÷ power supplied to the primary coil) × 100%

A. Efficiency of transformer = (secondary coil ÷ primary coil) × 100%

B. Efficiency of transformer = (mechanical advantage ÷ velocity ratio) × 100%

C. Efficiency of a transformer = (Number of turns in the secondary coil ÷ Number of turns in the primary coil) × 100%

D. Efficiency of a transformer = (power developed in the secondary coil ÷ power supplied to the primary coil) × 100%

The strength of an electromagnet increases with

A. Increases in the number of turn of the coil

B. Decreases in current with the coil

C. Increases in the distance between the pole

D. Increases in current without the coil

Lodestone is a natural magnet, it points at

A. N – W when suspended freely

C. S – E when suspended freely

A structural engineer stood on a top of a building releasing a light and heavy object to the ground which of the following statement is true?(Neglect Air Resistance)

A. Both the light and heavy subject reach the ground at the same time

B. The light object get to the ground first before the heavy object

C. The heavy object to the ground first before the light object

D. None get to the ground first

A vector quantity can only be completely described when ……… and …………are mentioned.

C. Distance and specified displacement

JAMB 2015

2015 JAMB Physics Past Questions

The 2015 JAMB Physics past questions with answers: 65 objective questions from the 2015 paper in the DeeepSolve question bank, each with its answer behind "Show answer". Try each question before you check, then practise the paper as a timed JAMB-style CBT.

Practise this paper as a timed JAMB-style CBT All JAMB Physics years

Questions

1.
The symbol −10X used to represent which of the particles?
1. A.Proton
2. B.Neutron
3. C.Electrons
4. D.Atoms
Show answer
Answer: C. Electrons
Get a step-by-step AI explanation in the app Get a step-by-step AI explanation in the app
2.
In which of the following device is the expansion of solid not required? I. Simple pendulum II. Fire alarms III. Thermostat IV. Bimetallic thermometer
1. A.III only
2. B.II & III only
3. C.I only
4. D.II, III & IV only
Show answer
Answer: C. I only
Get a step-by-step AI explanation in the app Get a step-by-step AI explanation in the app
3.
The r.m.s value of a supply voltage is quoted at 200v. What is the approximate peak value of the voltage?
1. A.200volts
2. B.300volts
3. C.283volts
4. D.250volts
Show answer
Answer: C. 283volts
Get a step-by-step AI explanation in the app Get a step-by-step AI explanation in the app
4.
The net movement of solvent molecules from a region of high solvent potential to a region of lower solvent potential through a partially or semi permeable membrane is refer to as
1. A.Diffusion
2. B.Osmosis
3. C.Surface tension
4. D.Cohesion
Show answer
Answer: B. Osmosis
AI explanation
1. Analyze the question
The question asks for the specific term used to describe the movement of solvent molecules (usually water) across a semi-permeable membrane from a region of high solvent potential to one of lower solvent potential.
2. Explain the concept
To understand this, we must distinguish between the terms provided:
Diffusion: This is the net movement of particles (atoms, ions, or molecules) from a region of higher concentration to a region of lower concentration. It does not require a membrane.
Osmosis: This is a special type of diffusion. It specifically refers to the movement of solvent molecules (like water) through a semi-permeable membrane. The membrane allows the solvent to pass through but restricts the movement of larger solute particles.
Surface Tension: This is a property of liquids that allows them to resist an external force, due to the cohesive nature of its molecules at the surface.
Cohesion: This refers to the force of attraction between molecules of the same substance.
3. Show the solution
The key phrase in the question is "through a partially or semi permeable membrane."
Whenever you see the movement of solvent molecules across a semi-permeable membrane, you are dealing with Osmosis.
In biological and physical contexts, "solvent potential" refers to the concentration of free water molecules. Water moves from where there is more water (high potential) to where there is less water (low potential) to balance the concentration on both sides of the membrane.
4. Identify the answer
Comparing our definition to the options provided, Osmosis is the correct term.
5. Tip
Memory Trick: Think of the word "OSMO". You can remember that Osmosis requires a Semi-permeable Membrane for Osmotic movement. If there is no membrane mentioned, it is just simple diffusion!
AI can make mistakes. Report anything that looks wrong.
5.
A good electric cell should have the following except
1. A.A minimum of polarization effect
2. B.A long life
3. C.A cheap and safe electrolytes
4. D.Cost and dangerous of the cell
Show answer
Answer: D. Cost and dangerous of the cell
Get a step-by-step AI explanation in the app Get a step-by-step AI explanation in the app
6.
If an object is placed at a height of tem above the ground at a stationary point. It posses what types of energy?
1. A.Mechanical energy
2. B.Stationary energy
3. C.Potential energy
4. D.Vibrational energy
Show answer
Answer: C. Potential energy
AI explanation
Analysis
The question asks us to identify the type of energy possessed by an object that is held at a specific height above the ground while remaining stationary.
Concept Explanation
In physics, energy is broadly categorized into two main forms:
Kinetic Energy: The energy an object possesses due to its motion. Since the object in the question is stationary (not moving), its kinetic energy is zero.
Potential Energy: The energy an object possesses due to its position or configuration. Specifically, Gravitational Potential Energy (GPE) is the energy stored in an object because of its height relative to a reference point (the ground).
The formula for gravitational potential energy is:
$PE = mgh$
Where:
m = mass of the object
g = acceleration due to gravity
h = height above the ground
Because the object is at a height ( $h$ ) and has mass ( $m$ ), it stores energy by virtue of its position.
Step-by-Step Solution
Evaluate the state of the object: The object is at a height ( $h > 0$ ) and is stationary ( $v = 0$ ).
Check Kinetic Energy: Since the velocity is zero, $KE = \frac{1}{2}mv^2 = 0$ .
Check Potential Energy: Since the object is at a height above the ground, it possesses gravitational potential energy ( $PE = mgh$ ).
Conclusion: An object held at a height possesses potential energy. While "Mechanical energy" is the sum of kinetic and potential energy, "Potential energy" is the specific and most accurate description of the energy stored due to its stationary position at a height.
Answer
The correct option is C.
Exam Tip
Whenever you see a question about an object at a "height," immediately think of Potential Energy. If the question mentions the object is "falling" or "moving," then you must consider Kinetic Energy or a combination of both (Mechanical Energy).
AI can make mistakes. Report anything that looks wrong.
7.
The device in which one circuit controls another, especially if the current in the second circuit is large or dangerous is known as
1. A.Electromagnetic devices
2. B.Magnetic relay device
3. C.None at all
4. D.Sextant
Show answer
Answer: B. Magnetic relay device
AI explanation
1. Analyze the question
The question asks for the name of a specific electrical device that acts as a switch. Its primary function is to allow a low-power or safe circuit to control a separate circuit that might carry a high voltage or a large, dangerous current.
2. Explain the concept
This device is based on the principle of electromagnetism.
How it works: When a small current flows through the coil of the device, it creates a magnetic field. This magnetic field attracts a metal armature (a switch), which then closes or opens the contacts of the second, high-power circuit.
Why use it? It provides electrical isolation. By using a relay, the person operating the switch (e.g., a light switch or a remote control) is physically separated from the high-voltage circuit, preventing electric shocks and allowing for automation.
3. Show the solution
Option A (Electromagnetic devices): This is a broad category. While a relay is an electromagnetic device, the term is too general; it could refer to motors, generators, or speakers.
Option B (Magnetic relay device): This is the specific name for the switch described. It uses an electromagnet to operate a mechanical switch, making it the perfect answer for controlling high-current circuits safely.
Option C (None at all): Incorrect, as the device described exists.
Option D (Sextant): This is a navigational instrument used to measure the angle between two visible objects; it has nothing to do with electrical circuits.
4. Identify the answer
The correct device is a Magnetic relay. It is specifically designed to isolate control circuits from high-power load circuits.
5. Exam Tip
When you see the word "control" and "dangerous/large current" in a Physics question, immediately look for the word "Relay." Think of a relay as a "middleman" that does the dangerous work so you don't have to touch the high-voltage wires directly!
AI can make mistakes. Report anything that looks wrong.
8.
Body floats in fluid when its …………………
1. A.Displaces its own volume of the liquid (fluid)
2. B.Displaces its own weight of the fluid
3. C.Displace its own density of the fluid
4. D.Is no longer subjected to gravity
Show answer
Answer: B. Displaces its own weight of the fluid
AI explanation
Analysis of the Question
This question tests your understanding of Archimedes' Principle and the Law of Flotation. To solve this, we need to look at the forces acting on a body that is floating in a fluid.
Concept Explanation
When a body is placed in a fluid, two main vertical forces act on it:
Weight ( $W$ ): The downward force due to gravity acting on the body.
Upthrust ( $U$ ): The upward force exerted by the fluid on the body.
According to Archimedes' Principle, the upthrust on an object submerged in a fluid is equal to the weight of the fluid displaced by the object.
For a body to float (stay in equilibrium without sinking or rising), the downward force must exactly balance the upward force. Therefore:
Weight of the body = Upthrust
Since Upthrust = Weight of the fluid displaced, it follows that:
Weight of the body = Weight of the fluid displaced
Step-by-Step Solution
Identify the condition for floating: A body floats when it is in equilibrium.
Apply the Law of Flotation: The Law of Flotation states that a floating body displaces its own weight of the fluid in which it floats.
Evaluate the options: • Option A is incorrect because a body only displaces its own volume if it is fully submerged. • Option B aligns perfectly with the Law of Flotation. • Option C is physically incorrect as you cannot displace "density." • Option D is incorrect because gravity is always acting on the body; it is the balance of forces that keeps it floating, not the absence of gravity.
Conclusion
The correct condition for a body to float is that it must displace a volume of fluid whose weight is equal to the weight of the body itself.
Exam Tip: Always remember the phrase: "A floating body displaces its own weight." If the question asked about a submerged body, the answer would be that it displaces its own volume. Don't mix these two up in the exam hall!
AI can make mistakes. Report anything that looks wrong.
9.
The resultant force of a couple is ………?
1. A.Infinity
2. B.Zero
3. C.One
4. D.Half
Show answer
Answer: B. Zero
AI explanation
1. Analyze the Question
The question asks for the resultant force of a "couple" in mechanics. A couple is a specific system of forces acting on a body.
2. Explain the Concept
In physics, a couple is defined as a pair of forces that are:
Equal in magnitude.
Parallel to each other.
Acting in opposite directions.
Separated by a perpendicular distance (the arm of the couple).
Because the two forces are equal and act in exactly opposite directions, they cancel each other out when you sum them up vectorially. However, they do not cancel out the turning effect (moment) of the forces; instead, they produce a rotation.
3. Show the Solution
Let the two forces be $F_1$ and $F_2$ .
By definition of a couple, $F_1 = F$ and $F_2 = -F$ (the negative sign indicates the opposite direction).
To find the resultant force ( $F_R$ ), we add the forces together: $F_R = F_1 + F_2$ $F_R = F + (-F)$ $F_R = 0$
Since the resultant force is zero, a couple cannot cause a body to undergo linear acceleration; it can only cause the body to rotate about its center of mass.
4. Identify the Answer
The resultant force of a couple is always zero. Therefore, the correct option is B.
5. Exam Tip
Remember the "Couple Rule": Resultant Force = 0, but Resultant Moment $\neq$ 0. If you ever see a question about a couple, immediately think of a steering wheel—you push up with one hand and pull down with the other with equal force; the wheel doesn't move left or right (resultant force is zero), but it spins (moment is produced).
AI can make mistakes. Report anything that looks wrong.
10.
Primary colours of light are
1. A.Red, blue and green
2. B.Cyan, magneta and yellow
3. C.Black, blue and green
4. D.None of these colours
Show answer
Answer: A. Red, blue and green
AI explanation
Analysis
The question asks for the primary colours of light. In physics, specifically in the study of optics, primary colours are defined as the set of colours that can be combined in different intensities to produce a broad range of other colours.
Explanation
Primary Colours of Light (Additive Mixing): When we talk about light (as opposed to pigments or paints), the primary colours are Red, Green, and Blue (RGB). When these three colours are mixed together in equal intensity, they produce white light. This is the principle used in television screens, computer monitors, and smartphone displays.
Secondary Colours: When you mix two primary colours of light, you get secondary colours: • Red + Green = Yellow • Green + Blue = Cyan • Blue + Red = Magenta
Distinction: Do not confuse these with the primary colours of pigments (subtractive mixing), which are Cyan, Magenta, and Yellow (CMY), often used in printing.
Step-by-Step Solution
Identify the context: The question specifically asks for the primary colours of light.
Recall the additive colour theory: The fundamental colours that cannot be created by mixing other colours of light are Red, Green, and Blue.
Evaluate the options: • Option A: Red, blue, and green (Matches the additive primary colours). • Option B: Cyan, magenta, and yellow (These are secondary colours of light or primary colours of pigments). • Option C: Black is the absence of light, so it cannot be a primary colour. • Option D: Incorrect, as Option A is valid.
Conclusion
The primary colours of light are Red, Green, and Blue. Therefore, Option A is the correct answer.
Exam Tip
To remember this easily, think of the acronym RGB. Just remember that your phone screen (which emits light) uses RGB pixels to create every image you see!
AI can make mistakes. Report anything that looks wrong.
11.
For a best result using temperature to achieve an accurate measurement, it is best to use
1. A.Mercury thermometer
2. B.gas thermometer
3. C.clinical thermometer
4. D.alcohol thermometer
Show answer
Answer: B. gas thermometer
AI explanation
Analysis
The question asks for the most accurate type of thermometer among the options provided. Accuracy in thermometry depends on the range of temperature being measured and the sensitivity of the substance used to expand or change properties in response to heat.
Concept Explanation
Mercury Thermometer: Reliable for everyday use, but mercury freezes at -39°C and boils at 357°C, limiting its range.
Gas Thermometer: These operate based on the laws of gases (like Charles's Law and the Pressure Law). Because gases expand much more uniformly and predictably than liquids over a very wide range of temperatures, they are considered the "gold standard" for calibration. They are used to define the International Temperature Scale because they provide the most consistent and accurate readings across a vast range of temperatures.
Clinical Thermometer: Designed specifically for human body temperature (a very narrow range). It is accurate for its specific purpose but not for general scientific measurement.
Alcohol Thermometer: Useful for very low temperatures (since alcohol has a low freezing point), but it is less accurate than mercury or gas thermometers because alcohol is not as uniform in its expansion.
Step-by-Step Solution
Evaluate the options based on physical principles: Liquids (mercury/alcohol) are subject to the limitations of their specific expansion coefficients, which can vary slightly at extreme temperatures.
Consider the Gas Law: Gases behave more like an "ideal gas" as pressure decreases. A constant-volume gas thermometer is highly sensitive and provides a standard against which other thermometers are calibrated.
Conclusion: Because gas thermometers are used to calibrate other types of thermometers and cover a much wider, more precise range of temperatures, they are the most accurate choice for scientific measurement.
This aligns with the scientific consensus that gas thermometers are the standard for high-precision temperature measurement.
Exam Tip
When you see questions about "accuracy" or "standard" in thermometry, always look for the gas thermometer. If the question asks about "sensitivity" or "low-temperature measurement," consider alcohol. If it asks about "convenience" or "daily laboratory use," mercury is usually the answer.
AI can make mistakes. Report anything that looks wrong.
12.
If an object whose mass is 3kg moves in a circular path of a radius 0.7m, records a speed at 2m/s. What is the result of the angular velocity?
1. A.4 rads–1
2. B.1rads–1–1
3. C.3–1rads–1
4. D.4rads–1–1
Show answer
Answer: A. 4 rads–1
Get a step-by-step AI explanation in the app Get a step-by-step AI explanation in the app
13.
If the velocity ratio of a machine is 5. What is its ratio of x and y?
1. A.2 : 5
2. B.1 : 5
3. C.5 : 1
4. D.3 : 1
Show answer
Answer: A. 2 : 5
Get a step-by-step AI explanation in the app Get a step-by-step AI explanation in the app
14.
Neutron were discovered by
1. A.J.J. Thompson
2. B.James Chadwick
3. C.Michael faraday
4. D.Dalton
Show answer
Answer: B. James Chadwick
AI explanation
Analysis
The question asks for the scientist credited with the discovery of the neutron, a subatomic particle found in the nucleus of an atom.
Concept Explanation
To answer this, we look at the history of atomic structure:
J.J. Thomson: Discovered the electron in 1897 using cathode ray tubes.
James Chadwick: In 1932, he performed an experiment bombarding beryllium atoms with alpha particles. He observed that a neutral radiation was emitted, which he identified as the neutron.
Michael Faraday: Known for his work on electromagnetism and electrochemistry, not subatomic particle discovery.
John Dalton: Proposed the atomic theory in the early 19th century, stating that atoms were indivisible spheres; he did not discover subatomic particles.
Step-by-Step Solution
Evaluate the options: We eliminate Dalton (atomic theory) and Faraday (electromagnetism).
Compare Thomson and Chadwick: Thomson is famous for the "Plum Pudding" model and the electron. Chadwick is specifically famous for proving the existence of the neutron, which had been theorized but remained elusive because it carries no electrical charge.
Conclusion: James Chadwick’s experimental evidence in 1932 is the universally accepted scientific discovery of the neutron.
Exam Tip
A simple mnemonic to remember these discoveries:
Proton = Rutherford
Electron = Thomson (Think: "T" for Thomson, "E" for Electron)
Neutron = Chadwick (Think: "NC" for Neutron Chadwick)
AI can make mistakes. Report anything that looks wrong.
15.
The two liquids which are often used in thermometer on experiment basic is known as
1. A.Mercury only
2. B.Alcohol and Water
3. C.Mercury and Alcohol
4. D.Alcohol only
Show answer
Answer: C. Mercury and Alcohol
AI explanation
Analysis of the Question
This question tests your knowledge of thermometric substances. It asks you to identify the two liquids commonly used in liquid-in-glass thermometers for scientific experiments and general temperature measurement.
Concept Explanation
A thermometric substance is a material that undergoes a measurable, regular physical change when its temperature changes. For a liquid to be suitable for a thermometer, it must:
Expand uniformly with temperature.
Have a high boiling point and a low freezing point to cover a wide range of temperatures.
Be easily visible (often colored).
Not stick to the walls of the glass capillary tube.
Mercury and Alcohol are the two most common liquids used because they meet these criteria effectively.
Mercury is excellent for high temperatures because it has a high boiling point ( $357^\circ\text{C}$ ) and does not wet glass.
Alcohol (usually colored ethanol) is excellent for low temperatures because it has a very low freezing point ( $-115^\circ\text{C}$ ), making it ideal for measuring cold environments where mercury would freeze.
Step-by-Step Solution
Evaluate Option A: Mercury is used, but it is not the only liquid used in thermometers.
Evaluate Option B: Water is never used in thermometers because it is transparent, has a small range of expansion, and wets glass, which makes it inaccurate.
Evaluate Option C: Mercury and Alcohol are the two standard liquids used in laboratory and clinical thermometers. This aligns with the physical properties required for accurate temperature measurement.
Evaluate Option D: Alcohol is used, but mercury is also a standard liquid, so this is incomplete.
Conclusion
Based on the principles of thermal physics, Mercury and Alcohol are the two primary liquids used in thermometers.
Exam Tip: Remember the "Mercury vs. Alcohol" rule: Mercury is for high temperatures (it's a metal, so it's robust), and Alcohol is for low temperatures (it stays liquid even in freezing conditions).
AI can make mistakes. Report anything that looks wrong.
16.
Which of the following instrument is most accurately for comparing electromotive force (e.m.f) of two cells?
1. A.Voltmeter
2. B.Meter rule
3. C.Galvanometer
4. D.Potentiometer
Show answer
Answer: D. Potentiometer
AI explanation
Analysis
The question asks for the most accurate instrument to compare the electromotive force (e.m.f.) of two cells. In physics, accuracy is determined by how well an instrument can measure a value without drawing current from the source, which would otherwise cause a voltage drop due to internal resistance.
Concept Explanation
Voltmeter (Option A): A voltmeter has a finite internal resistance. When connected across a cell, it draws a small amount of current. This causes a potential drop across the internal resistance of the cell, meaning the voltmeter measures the terminal potential difference rather than the true e.m.f.
Potentiometer (Option D): A potentiometer works on the null-point principle. When the circuit is balanced (the galvanometer shows zero deflection), no current flows from the cell being tested. Because no current is drawn, the potential difference measured is exactly equal to the e.m.f. of the cell. This makes it the most accurate method for comparing e.m.f.s.
Galvanometer (Option C): A galvanometer is used to detect the presence of current, not to measure e.m.f. directly.
Meter rule (Option B): A meter rule is a tool for measuring length, not electrical potential.
Step-by-Step Solution
Understand the requirement: To compare e.m.f. accurately, we must measure the potential difference when the cell is in an "open circuit" (no current flowing).
Evaluate the instruments: • Voltmeters are convenient but introduce errors because they draw current. • Potentiometers use a sliding contact to find a point where the potential difference of the cell is balanced by a potential drop across a wire, resulting in zero current flow.
Conclusion: Since the potentiometer draws no current at the balance point, it provides the most precise and accurate comparison of e.m.f.s.
Exam Tip
Whenever you see a question about "accuracy" in measuring e.m.f. or internal resistance, always look for the Potentiometer. Remember: Potentiometer = Null-point = No current drawn = High accuracy.
AI can make mistakes. Report anything that looks wrong.
17.
A member of the crew of a SPACESHIP experiences weightlessness in a space when they
1. A.Fall freely from the earth’s gravitational field
2. B.Is walking on the planet
3. C.In between the sun and the earth
4. D.Holding anything in space is negative
Show answer
Answer: A. Fall freely from the earth’s gravitational field
AI explanation
Analysis of the Question
The question asks for the physical condition that leads to the sensation of "weightlessness" for an astronaut or crew member in a spaceship.
Concept Explanation
Weightlessness does not mean that gravity has disappeared. Instead, it occurs when there is no normal reaction (the upward force exerted by a surface) acting on an object.
In physics, we define weight as the force with which a body presses against a surface. If you are standing on a scale, the scale measures the normal reaction. When you are in a state of "free fall," both you and the container (the spaceship) are accelerating towards the center of the earth at the same rate (acceleration due to gravity, $g$ ). Because you are falling at the same rate as the floor, you do not press against the floor, and the floor does not push back on you. Therefore, your apparent weight becomes zero.
Step-by-Step Solution
Evaluate Option B: Walking on a planet provides a surface that exerts a normal reaction force on your feet. You feel your weight clearly here.
Evaluate Option C: Being in between the sun and the earth does not automatically guarantee weightlessness; you would still be subject to gravitational pulls from both bodies.
Evaluate Option D: This statement is physically nonsensical in the context of gravitational mechanics.
Evaluate Option A: When an object is in orbit or traveling through space, it is essentially in a state of continuous free fall around the Earth. Because the spaceship and the crew are falling together at the same acceleration, the crew experiences no contact force from the walls or floor of the ship. This state of "free fall" is the definition of weightlessness.
Conclusion
The sensation of weightlessness experienced by astronauts is due to the fact that they are in a state of free fall within the gravitational field.
Exam Tip: Always remember that "weightlessness" is a state of apparent weightlessness. Gravity is still acting on the astronaut (which is why the ship stays in orbit), but because the astronaut and the ship are accelerating at the same rate, the astronaut feels no weight.
AI can make mistakes. Report anything that looks wrong.
18.
At what respective value of a, b, and c would the unit of work, the joule, be dimensionally similar to Ma Lb Tc?
1. A.1, – 2, 1
2. B.1, 2, – 2
3. C.1, 1, –2
4. D.2, 2, 1
Show answer
Answer: B. 1, 2, – 2
Get a step-by-step AI explanation in the app Get a step-by-step AI explanation in the app
19.
The normal temperature of human body is record at what ranges?
1. A.27°C to 43°C
2. B.30°C to 40°
3. C.98.4°C only
4. D.Between 35°C to 37°C
Show answer
Answer: D. Between 35°C to 37°C
Get a step-by-step AI explanation in the app Get a step-by-step AI explanation in the app
20.
The direction of the path taken by light is called
1. A.Locus
2. B.Lines
3. C.Ray
4. D.Beam
Show answer
Answer: C. Ray
AI explanation
1. Analyze the question
The question asks for the specific term used in physics to describe the path along which light energy travels.
2. Explain the concept
In optics (the study of light), we use specific terminology to describe how light moves:
Ray: This is a mathematical line representing the direction of the path taken by light. It is usually represented by a straight line with an arrow indicating the direction of travel.
Beam: This is a collection or bundle of many light rays traveling together.
Locus: This is a mathematical term referring to a set of points that satisfy a particular condition; it is not specific to light.
Lines: While light travels in straight lines (rectilinear propagation), "line" is a general geometric term, whereas "ray" is the specific scientific term used in physics to denote the direction of light's path.
3. Show the solution
When we represent light moving from a source, we draw a straight line with an arrow. This representation is scientifically defined as a ray.
A single ray represents the direction of the path.
If we have many rays moving together (like from a torchlight), we call that a beam.
Since the question specifically asks for the "direction of the path taken by light," the most accurate term is "Ray."
4. Identify the answer
Comparing our analysis to the options provided:
A. Locus (Incorrect)
B. Lines (Incorrect - too general)
C. Ray (Correct)
D. Beam (Incorrect - this refers to a collection of rays)
5. Tip
Think of it this way: A Ray is the "path" (the direction), while a Beam is the "traffic" (the collection of many rays). Always remember that a ray is a single line with an arrow!
AI can make mistakes. Report anything that looks wrong.
21.
What is the inductance (L) of an inductor whose reactance is 1Ω at 50/ π hertz (H)?
1. A.100 H
2. B.0.01H
3. C.10H
4. D.1H
Show answer
Answer: B. 0.01H
AI explanation
1. Analyze the question
We are given:
Inductive Reactance ( $X_L$ ) = $1 \, \Omega$
Frequency ( $f$ ) = $\frac{50}{\pi} \, \text{Hz}$
We need to find the Inductance ( $L$ ).
2. Explain the concept
In an AC circuit, the inductive reactance ( $X_L$ ) is the opposition offered by an inductor to the flow of alternating current. The formula relating these variables is:
$X_L = 2\pi fL$
Where:
$X_L$ is the inductive reactance in Ohms ( $\Omega$ )
$f$ is the frequency in Hertz (Hz)
$L$ is the inductance in Henry (H)
3. Show the solution
Step 1: Substitute the given values into the formula:
$1 = 2 \times \pi \times \left( \frac{50}{\pi} \right) \times L$
Step 2: Simplify the right side of the equation. Notice that the $\pi$ in the numerator and the $\pi$ in the denominator cancel each other out:
$1 = 2 \times 50 \times L$
$1 = 100 \times L$
Step 3: Solve for $L$ by dividing both sides by 100:
$L = \frac{1}{100}$
$L = 0.01 \, \text{H}$
4. Identify the answer
Comparing our result to the given options, $0.01 \, \text{H}$ corresponds to option B.
5. Tip
When dealing with AC circuit formulas involving frequency, always look for opportunities to cancel out $\pi$ . In many JAMB physics questions, the frequency is intentionally given as a fraction of $\pi$ (like $50/\pi$ or $100/\pi$ ) specifically to make the calculation easier by canceling the $\pi$ in the $2\pi fL$ or $1/2\pi fC$ formulas.
AI can make mistakes. Report anything that looks wrong.
22.
In an elastic collision I. Energy is conserved II. Energy is decreased III. Energy is increased IV. Linear momentum conserved
1. A.I only
2. B.I and IV only
3. C.II only
4. D.III only
Show answer
Answer: B. I and IV only
Get a step-by-step AI explanation in the app Get a step-by-step AI explanation in the app
23.
A motor boy of a driver saw what seems to appear to be a pool of water a head of him, while his driver drives a new truck on a sunny day. Which of the following explains his observation?
1. A.He saw a flying objects
2. B.He must be thinking of water and food
3. C.He was seeing the shadow of the car
4. D.The sun ray from the sky were passing from a hot air (layer) to cold layer
Show answer
Answer: D. The sun ray from the sky were passing from a hot air (layer) to cold layer
AI explanation
Analysis of the Question
This question tests your understanding of Optics, specifically the phenomenon of Refraction and Total Internal Reflection as they relate to atmospheric conditions. The observation described is a classic example of a mirage.
Explanation of the Concept
A mirage occurs on hot, sunny days when the air near the ground becomes significantly hotter (and therefore less dense) than the air higher up.
Temperature Gradient: As the sun heats the road surface, the layer of air immediately above the road becomes very hot. The air layers above that remain cooler and denser.
Refraction: Light rays from the sky travel from the cooler, denser air into the hotter, less dense air. According to Snell's Law, when light travels from a denser medium to a less dense medium, it bends away from the normal.
Total Internal Reflection: As the light rays continue to bend away from the normal, they eventually hit the hot air layer at an angle greater than the critical angle. At this point, the light undergoes Total Internal Reflection and is reflected upwards toward the observer's eye.
The Illusion: The observer's brain assumes light travels in a straight line. When the reflected light reaches the eye, the brain traces it back to the ground, creating the illusion of a shimmering pool of water (which is actually just an image of the blue sky).
Step-by-Step Solution
Step 1: Identify the phenomenon. The "pool of water" on a hot road is a mirage.
Step 2: Evaluate the physics. Mirages are caused by the variation in the refractive index of air due to temperature differences.
Step 3: Analyze the options. • A, B, and C are psychological or incorrect physical explanations. • D describes the transition of light through air layers of different temperatures (densities), which is the fundamental cause of the refraction and reflection that creates the mirage.
Conclusion
While the phrasing in option D ("passing from a hot air to cold layer") is a simplified way of describing the temperature gradient, it correctly identifies that the phenomenon is caused by light passing through air layers of different temperatures.
Exam Tip: Whenever you see a question about a "mirage," "shimmering road," or "oases in the desert," always look for keywords like refraction, total internal reflection, or temperature gradient. These are the physics principles that govern these illusions!
AI can make mistakes. Report anything that looks wrong.
24.
A stroboscope can be used to make the wave appear …………..
1. A.Stationary
2. B.In motion
3. C.Dipper
4. D.Ripple
Show answer
Answer: A. Stationary
AI explanation
Analysis
The question asks for the effect of using a stroboscope on a wave. A stroboscope is an instrument used to make a cyclically moving object appear to be slow-moving or stationary.
Concept Explanation
A stroboscope works by emitting short, rapid flashes of light at a specific frequency. When the frequency of the flashes matches the frequency of the wave (or is a multiple of it), the wave appears to be "frozen" in time. This phenomenon is known as stroboscopic effect.
In physics experiments involving ripples in a ripple tank, we use a stroboscope to observe the wavelength and frequency of the waves more clearly. By adjusting the flash rate, we can make the rapidly moving wave crests appear to stop moving, allowing us to measure them accurately.
Step-by-Step Solution
Identify the function of the device: A stroboscope is designed to observe periodic motion.
Relate to wave motion: When a wave is moving at a high frequency, it is difficult for the human eye to track individual crests or troughs.
Apply the strobe effect: By flashing light at the same frequency as the wave, the eye only sees the wave at the same position in each cycle.
Conclusion: Because the eye sees the wave at the same position repeatedly, the brain perceives the wave as not moving at all.
Identifying the Answer
Comparing this to the options provided:
A. Stationary: This matches the physical principle of the stroboscopic effect.
B. In motion: This is what the wave is doing naturally, but the stroboscope is used to stop this perception.
C. Dipper: This is a component of a ripple tank, not the effect of a stroboscope.
D. Ripple: This is the object being observed, not the visual effect produced.
Exam Tip
Whenever you see a question about a "stroboscope" in your Physics exam, immediately associate it with the word "stationary" or "frozen." It is a common trick in JAMB to ask about the purpose of this device; just remember it is used to "stop" motion for easier measurement.
AI can make mistakes. Report anything that looks wrong.
25.
The eyeball consists of a round tough white skin called
1. A.Sclerotic
2. B.Choroid coal
3. C.Optical fiber
4. D.Accommodation
Show answer
Answer: A. Sclerotic
AI explanation
1. Analyze the question
The question asks for the specific name of the outer, tough, white layer of the human eyeball. This is a common biology/physics (optics) question regarding the structure of the eye.
2. Explain the concept
The human eye is composed of three main layers:
The Sclera (Sclerotic layer): This is the outermost, tough, white, fibrous layer. Its primary function is to protect the inner parts of the eye and maintain the shape of the eyeball.
The Choroid: This is the middle layer, which is rich in blood vessels and contains dark pigments to prevent internal reflection of light.
The Retina: This is the innermost layer where light-sensitive cells (rods and cones) are located, acting as the screen where images are formed.
3. Show the solution
Option A (Sclerotic): This refers to the sclera. It is the tough, white, outer coat of the eye. This matches the description in the question.
Option B (Choroid coat): This is the vascular middle layer, not the tough white outer skin.
Option C (Optical fiber): This is a technology used for transmitting light signals, not a part of the human eye.
Option D (Accommodation): This is the process by which the eye changes its focal length to focus on objects at different distances; it is a function, not a physical layer of the eye.
4. Identify the answer
Based on the anatomical structure of the eye, the tough white outer skin is the Sclerotic layer (or Sclera).
5. Tip
To remember the layers of the eye from outside to inside, use the mnemonic "SCR":
Sclera (Tough, white outer layer)
Choroid (Middle, blood-rich layer)
Retina (Inner, light-sensitive layer)
AI can make mistakes. Report anything that looks wrong.
26.
Quantities of heat Q can be measured using a container called
1. A.Thermometer
2. B.Measuring cylinder
3. C.Calorimeter
4. D.Meter rule
Show answer
Answer: C. Calorimeter
Get a step-by-step AI explanation in the app Get a step-by-step AI explanation in the app
27.
Efficiency of a transformer is equal to
1. A.Efficiency of transformer = (secondary coil ÷ primary coil) × 100%
2. B.Efficiency of transformer = (mechanical advantage ÷ velocity ratio) × 100%
3. C.Efficiency of a transformer = (Number of turns in the secondary coil ÷ Number of turns in the primary coil) × 100%
4. D.Efficiency of a transformer = (power developed in the secondary coil ÷ power supplied to the primary coil) × 100%
Show answer
Answer: D. Efficiency of a transformer = (power developed in the secondary coil ÷ power supplied to the primary coil) × 100%
AI explanation
Analysis
The question asks for the definition of the efficiency of a transformer. In physics, efficiency is a measure of how well a device converts input energy into useful output energy.
Concept Explanation
A transformer is an electrical device that changes voltage levels. Ideally, a transformer would have 100% efficiency, meaning no energy is lost. However, in reality, energy is lost due to factors like heat (resistance in the coils), eddy currents, and magnetic flux leakage.
The efficiency ( $\eta$ ) of any machine or electrical device is defined as the ratio of the useful output power to the total input power, expressed as a percentage:
$\text{Efficiency} (\eta) = \frac{\text{Output Power}}{\text{Input Power}} \times 100\%$
In a transformer:
Input Power is the power supplied to the primary coil ( $P_p = V_p I_p$ ).
Output Power is the power developed in the secondary coil ( $P_s = V_s I_s$ ).
Step-by-Step Solution
Evaluate Option A: This is vague and does not specify what property of the coils is being measured. It is incorrect.
Evaluate Option B: This is the formula for the efficiency of a simple machine (like a pulley or lever), not an electrical transformer.
Evaluate Option C: This is the formula for the turns ratio of a transformer, which relates voltage and current, but it does not define efficiency.
Evaluate Option D: This correctly identifies the ratio of output power (secondary) to input power (primary) as the definition of efficiency.
Conclusion
The efficiency of a transformer is the ratio of the power output from the secondary coil to the power input at the primary coil. This matches the definition provided in option D.
Exam Tip: Always remember that "Efficiency" in physics is almost always (Output / Input) × 100%. If you are ever confused in an exam, look for the option that represents "what you get" divided by "what you put in."
AI can make mistakes. Report anything that looks wrong.
28.
The dimension of universal gravitational constant is……….?
1. A. $M^{–1}L^3 T^{–2}$
2. B.ML3T2
3. C.ML3
4. D.MLT-2
Show answer
Answer: A. $M^{–1}L^3 T^{–2}$
Get a step-by-step AI explanation in the app Get a step-by-step AI explanation in the app
29.
Mr. F. Abioye observed his image through a plane mirror, kept at a distance 4.7m away from him in his room. At what distance is the image found from Abioye's eye?
1. A.9.4m
2. B.7.5m
3. C.5.7m
4. D.6.9m
Show answer
Answer: A. 9.4m
AI explanation
Analysis of the Question
The question asks for the distance between Mr. Abioye and his image as seen in a plane mirror. You are given the distance between the object (Mr. Abioye) and the mirror.
Concept: Properties of Plane Mirrors
In physics, plane mirrors follow specific laws of reflection:
Object Distance = Image Distance: The distance of the object from the mirror ( $u$ ) is exactly equal to the distance of the image from the mirror ( $v$ ).
Virtual Image: The image formed is virtual and appears to be located behind the mirror at the same distance as the object is in front of it.
Step-by-Step Solution
Identify the given values: • Distance from Mr. Abioye to the mirror ( $u$ ) = 4.7 m. • Since the image is formed at the same distance behind the mirror, the distance from the mirror to the image ( $v$ ) = 4.7 m.
Calculate the total distance: • The question asks for the distance from Mr. Abioye to his image. • This distance is the sum of the distance from Mr. Abioye to the mirror plus the distance from the mirror to the image. • Total distance = $u + v$ • Total distance = 4.7 m + 4.7 m • Total distance = 9.4 m
Conclusion
The image is located 9.4 meters away from Mr. Abioye.
Exam Tip
Always remember that in plane mirror problems, the "total distance" is usually double the distance between the object and the mirror. If the question asks for the distance between the object and the mirror, it is 4.7m; if it asks for the distance between the object and the image, it is 9.4m. Read the question carefully to see which one is being requested!
AI can make mistakes. Report anything that looks wrong.
30.
Electrons were discovered by
1. A.James Chadwick B.
2. B.J.J Thompson
3. C.Sir Isaac Newton
4. D.Charles Newton
Show answer
Answer: B. J.J Thompson
Get a step-by-step AI explanation in the app Get a step-by-step AI explanation in the app
31.
If the mechanical advantage of a machine is 4. What is its ratio for LOAD to EFFORT?
1. A.4:01
2. B.1:04
3. C.5:01
4. D.2:01
Show answer
Answer: A. 4:01
AI explanation
1. Analyze the question
The question asks for the relationship between Load and Effort, given that the Mechanical Advantage (M.A.) of a machine is 4.
2. Explain the concept
In Physics, the Mechanical Advantage (M.A.) of a machine is defined as the ratio of the Load ( $L$ ) to the Effort ( $E$ ). It measures how much a machine multiplies the force applied to it.
The formula is:
$\text{Mechanical Advantage (M.A.)} = \frac{\text{Load}}{\text{Effort}}$
When we express a ratio of $L:E$ , we are essentially looking for the value of $\frac{L}{E}$ .
3. Show the solution
Given: M.A. = 4
Formula: $\text{M.A.} = \frac{\text{Load}}{\text{Effort}}$
Substitution: $4 = \frac{\text{Load}}{\text{Effort}}$
To express this as a ratio ( $L:E$ ), we can write 4 as a fraction:
$\frac{4}{1} = \frac{\text{Load}}{\text{Effort}}$
Therefore, the ratio of Load to Effort is 4:1.
4. Identify the answer
Comparing our result to the given options: A. 4:1 B. 1:4 C. 5:1 D. 2:1
The correct option is A.
5. Tip
Always remember the acronym "LE" for Mechanical Advantage: Load over Effort. If you ever get confused, just think: "A machine with a high M.A. makes it easier to lift a heavy Load with a small Effort." Since 4 is greater than 1, the Load must be greater than the Effort!
AI can make mistakes. Report anything that looks wrong.
32.
Which one of the following is a vector quantity?
1. A.Temperature gradient
2. B.Mass
3. C.Work
4. D.Time
Show answer
Answer: A. Temperature gradient
AI explanation
1. Analyze the question
The question asks us to identify which of the listed physical quantities is a vector quantity. To solve this, we must distinguish between scalar and vector quantities.
2. Explain the concept
Scalar Quantities: These are physical quantities that have only magnitude (size) but no specific direction. Examples include mass, time, work, energy, distance, and temperature.
Vector Quantities: These are physical quantities that have both magnitude and a specific direction. Examples include displacement, velocity, force, acceleration, and gradients (like temperature gradient or potential gradient).
3. Show the solution
Let's evaluate each option:
B. Mass: Mass is a measure of the amount of matter in an object. It has magnitude (e.g., 5kg) but no direction. It is a scalar.
C. Work: Work is defined as the product of force and displacement in the direction of the force. Even though it involves force and displacement (both vectors), the result of their dot product is a scalar. It has no direction. It is a scalar.
D. Time: Time is a measure of duration. It has magnitude (e.g., 10 seconds) but does not have a direction. It is a scalar.
A. Temperature gradient: A gradient represents the rate of change of a quantity with respect to distance. Because it indicates the direction in which the temperature changes most rapidly (from hot to cold), it possesses both magnitude and direction. Therefore, it is a vector.
4. Identify the answer
Based on the definitions above, the temperature gradient is the only vector quantity listed.
5. Tip
A simple way to remember vectors is the acronym "FAT VED": Force, Acceleration, Torque, Velocity, Electric field, and Displacement. If a quantity is a "gradient" of a scalar field, it is almost always a vector!
AI can make mistakes. Report anything that looks wrong.
33.
The property of a body to remain at rest or to continue to move in a straight line is known as
1. A.force
2. B.Impulse
3. C.Energy
4. D.Inertia
Show answer
Answer: D. Inertia
AI explanation
Analysis
The question asks for the specific physical property of matter that resists any change in its state of rest or uniform motion in a straight line. This is a fundamental concept in classical mechanics, specifically related to Newton's First Law of Motion.
Concept Explanation
This concept is defined by Newton’s First Law of Motion, often called the Law of Inertia.
Inertia is the inherent property of a body that makes it resist any change in its state of rest or motion.
If an object is stationary, it wants to stay stationary.
If an object is moving at a constant velocity, it wants to keep moving at that same velocity in the same direction.
An external force is required to overcome this inertia to change the object's state.
Let's look at why the other options are incorrect:
Force: This is the agent (a push or a pull) that causes a change in the state of rest or motion; it is not the property of the body itself.
Impulse: This is the product of force and the time for which it acts, which results in a change in momentum.
Energy: This is the capacity to do work.
Step-by-Step Solution
Identify the definition: The statement "the property of a body to remain at rest or to continue to move in a straight line" is the textbook definition of inertia.
Relate to Newton's Laws: Since Newton's First Law states that an object will maintain its state unless acted upon by an external force, the "resistance" to that change is what we call inertia.
Match with options: Comparing this definition to the provided options, "Inertia" (Option D) is the correct term.
Conclusion
Exam Tip: Think of "Inertia" as "Laziness." Just as a lazy person prefers to stay in bed (at rest) and keep doing what they are already doing, an object with inertia prefers to keep doing exactly what it is currently doing!
AI can make mistakes. Report anything that looks wrong.
34.
A radioactive source emits X–rays of very short wavelength (10 $^{-13}$ m ). What is the frequency of these rays?
1. A.2 × 1018HZ
2. B.3 × 10 19HZ
3. C.3 × 1021HZ
4. D.3 × 10-19HZ
Show answer
Answer: C. 3 × 1021HZ
AI explanation
1. Analyze the question
We are given the wavelength ( $\lambda$ ) of X-rays and asked to calculate the frequency ( $f$ ). We know that X-rays are electromagnetic waves, which means they travel at the speed of light ( $c$ ).
2. Explain the concept
The relationship between the speed of a wave, its frequency, and its wavelength is given by the wave equation:
$c = f \times \lambda$
Where:
$c$ is the speed of light in a vacuum, approximately $3.0 \times 10^8 \text{ m/s}$ .
$f$ is the frequency in Hertz (Hz).
$\lambda$ (lambda) is the wavelength in meters (m).
To find the frequency, we rearrange the formula:
$f = \frac{c}{\lambda}$
3. Show the solution
Given:
$c = 3.0 \times 10^8 \text{ m/s}$
$\lambda = 10^{-13} \text{ m}$
Calculation:
$f = \frac{3.0 \times 10^8}{10^{-13}}$
Using the laws of indices, when you divide powers of the same base, you subtract the exponents:
$f = 3.0 \times 10^{8 - (-13)}$
$f = 3.0 \times 10^{8 + 13}$
$f = 3.0 \times 10^{21} \text{ Hz}$
4. Identify the answer
Comparing our result to the given options: A. $2 \times 10^{18} \text{ Hz}$ B. $3 \times 10^{19} \text{ Hz}$ C. $3 \times 10^{21} \text{ Hz}$ D. $3 \times 10^{-19} \text{ Hz}$
The calculated value matches option C.
5. Tip
When dealing with electromagnetic wave problems in JAMB, always remember that the speed of light ( $c = 3 \times 10^8 \text{ m/s}$ ) is a constant you are expected to know. Also, pay close attention to the laws of indices—a common mistake is to accidentally add the exponents instead of subtracting them when dividing, or getting the sign wrong when subtracting a negative number!
AI can make mistakes. Report anything that looks wrong.
35.
What is the relationship mechanical advantage (MA) velocity Ratio (V.R) and efficiency with percentage?
1. A.e = M.A/V.R × 100 %
2. B.M.A = E.V.R
3. C.V.R = 1 ÷ sin θ M.A
4. D.M.A = 1/E × 100%
Show answer
Answer: A. e = M.A/V.R × 100 %
Get a step-by-step AI explanation in the app Get a step-by-step AI explanation in the app
36.
If a mango fruit dropped at a height of 50 meters. How long does it reach the ground? (take g = 10m/s2)
1. A.2 sec
2. B.3 sec
3. C.4sec
4. D.3.2sec
Show answer
Answer: D. 3.2sec
Get a step-by-step AI explanation in the app Get a step-by-step AI explanation in the app
37.
The optical instrument which is suitable for viewing a nearby objects is ………..?
1. A.Telescope
2. B.sextant
3. C.microscope
4. D.periscope
Show answer
Answer: C. microscope
AI explanation
Analysis
The question asks for the specific optical instrument designed to magnify and view objects that are very close to the observer (nearby objects).
Concept Explanation
Optical instruments are designed to manipulate light to help us see things more clearly. To determine the correct answer, let’s look at the function of each option:
Telescope: Designed to view distant objects (like stars or planets) by gathering light and bringing the image closer.
Sextant: A navigational instrument used to measure the angular distance between two visible objects, primarily used for celestial navigation.
Microscope: Specifically designed to produce magnified images of very small, nearby objects that are otherwise invisible to the naked eye.
Periscope: Used to see over or around obstacles (like looking out of a submarine or over a wall) by using mirrors or prisms to reflect light.
Step-by-Step Solution
Evaluate the requirement: We need an instrument for "nearby objects."
Eliminate options: • A (Telescope) is for distant objects. • B (Sextant) is for navigation/measurement. • D (Periscope) is for viewing around obstacles, not necessarily for magnifying nearby objects.
Identify the fit: A microscope uses a combination of lenses to magnify tiny, nearby specimens, making it the standard instrument for this purpose.
Conclusion
The microscope is the optical instrument specifically engineered to view and magnify nearby objects that are too small to be seen clearly by the human eye.
Exam Tip: Always remember the "Distance Rule": Telescopes are for Things far away (T-T), while Microscopes are for Minute (small/nearby) things (M-M).
AI can make mistakes. Report anything that looks wrong.
38.
Which of the following will increase the boiling point of water? I. Taking it to a high altitude II. Dissolving a salt into it III. Heating it in a sealed flask IV. Increasing the rate of heat supply .
1. A.I only
2. B.III & IV only
3. C.II & III only
4. D.II only
Show answer
Answer: C. II & III only
AI explanation
To solve this problem, we need to understand the factors that influence the boiling point of a liquid. Boiling occurs when the saturated vapour pressure of a liquid equals the external atmospheric pressure.
1. Analyze the options
I. Taking it to a high altitude: At high altitudes, atmospheric pressure is lower. Since boiling point decreases as external pressure decreases, this will lower the boiling point.
II. Dissolving a salt into it: Adding a solute (like salt) to a solvent (water) causes "boiling point elevation." The solute particles interfere with the escape of water molecules into the vapour phase, requiring more heat to reach the boiling point. This increases the boiling point.
III. Heating it in a sealed flask: In a sealed flask, the vapour produced cannot escape. As the temperature rises, the pressure inside the flask increases above atmospheric pressure. Since boiling point increases with pressure, this increases the boiling point.
IV. Increasing the rate of heat supply: Increasing the heat supply only makes the water boil faster (the rate of evaporation increases), but it does not change the temperature at which the water boils. The boiling point remains constant once reached.
2. Explain the concept
Boiling Point Elevation: The presence of impurities or solutes increases the boiling point of a liquid.
Pressure-Boiling Point Relationship: The boiling point of a liquid is directly proportional to the external pressure exerted on its surface. Increasing the pressure (as in a pressure cooker or a sealed container) increases the boiling point.
3. Show the solution
Statement I is incorrect because lower pressure decreases the boiling point.
Statement II is correct because solutes elevate the boiling point.
Statement III is correct because a sealed container traps vapour, increasing the pressure and thus the boiling point.
Statement IV is incorrect because the rate of heating does not change the boiling point temperature.
Therefore, only statements II and III will increase the boiling point of water.
4. Identify the answer
Comparing our findings with the provided options, the correct choice is C.
5. Exam Tip
Remember the "Pressure-Boiling" rule: If you want to cook food faster (like beans), you use a pressure cooker. The pressure cooker traps steam, increasing the pressure inside, which raises the boiling point of water above $100^\circ\text{C}$ . Higher temperature means the food cooks faster!
AI can make mistakes. Report anything that looks wrong.
39.
The strength of an electromagnet increases with
1. A.Increases in the number of turn of the coil
2. B.Decreases in current with the coil
3. C.Increases in the distance between the pole
4. D.Increases in current without the coil
Show answer
Answer: A. Increases in the number of turn of the coil
Get a step-by-step AI explanation in the app Get a step-by-step AI explanation in the app
40.
Volatile liquids usually
1. A.Have high boiling points
2. B.have low boiling points
3. C.have high densities
4. D.have high melting points
Show answer
Answer: B. have low boiling points
AI explanation
Analysis
The question asks for the defining physical characteristic of "volatile liquids." To answer this, we need to understand what volatility means in the context of thermodynamics and molecular physics.
Concept Explanation
Volatility refers to the tendency of a substance to vaporize or turn into a gas at a given temperature.
A substance is considered "volatile" if it evaporates easily at room temperature.
Evaporation occurs when molecules at the surface of a liquid have enough kinetic energy to overcome the intermolecular forces holding them in the liquid state.
Liquids that evaporate easily have weak intermolecular forces. Because these forces are weak, it does not take much heat energy to break them, which results in a low boiling point.
Step-by-Step Solution
Define Volatility: Volatility is the measure of how easily a liquid turns into vapor.
Relate to Boiling Point: The boiling point is the temperature at which the vapor pressure of a liquid equals the external atmospheric pressure.
Analyze the Relationship: If a liquid is highly volatile, it exerts a high vapor pressure even at low temperatures. Therefore, it reaches the boiling point much faster (at a lower temperature) than a non-volatile liquid.
Evaluate Options: • A: Incorrect. High boiling points indicate strong intermolecular forces, which make a liquid stable and less likely to evaporate. • B: Correct. Low boiling points mean the liquid requires very little heat to transition into a gas, which is the definition of volatility. • C: Incorrect. Density is the mass per unit volume and is not directly related to the volatility of a liquid. • D: Incorrect. Melting point relates to the transition from solid to liquid, not liquid to gas.
Conclusion
Volatile liquids, such as petrol or methylated spirit, have weak intermolecular forces, which allow them to vaporize readily at low temperatures. This corresponds to having a low boiling point.
Exam Tip: Think of "volatile" as "flighty" or "quick to leave." If a liquid is quick to leave the liquid state and become a gas, it must have a low boiling point. This is a common JAMB question, so remember: High Volatility = Low Boiling Point.
AI can make mistakes. Report anything that looks wrong.
41.
Transformers are designed so that energy losses are reduced to a minimum. This is achieved through which of these process? I. Using a soft iron ore II. Laminating the iron core to reduce energy loses due to eddy current III. Designing an efficient iron core
1. A.I & II only
2. B.II only
3. C.I, II, & III only
4. D.III only
Show answer
Answer: C. I, II, & III only
Get a step-by-step AI explanation in the app Get a step-by-step AI explanation in the app
42.
An alternating current with a frequency of 100HZ has a period of
1. A.0.03sec
2. B.0.01sec
3. C.0.04sec
4. D.0.15sec
Show answer
Answer: B. 0.01sec
AI explanation
1. Analyze the question
You are asked to find the period ( $T$ ) of an alternating current given its frequency ( $f$ ).
2. Explain the concept
In physics, the period ( $T$ ) of a wave or an alternating current is defined as the time taken to complete one full cycle. The frequency ( $f$ ) is the number of cycles completed in one second.
The relationship between period and frequency is inverse:
$T = \frac{1}{f}$
Where:
$T$ is the period measured in seconds (s).
$f$ is the frequency measured in Hertz (Hz).
3. Show the solution
Given:
Frequency ( $f$ ) = $100\text{ Hz}$
Using the formula:
$T = \frac{1}{f}$
$T = \frac{1}{100}$
$T = 0.01\text{ seconds}$
4. Identify the answer
Comparing our result to the given options: A. 0.03sec B. 0.01sec C. 0.04sec D. 0.15sec
The correct option is B.
5. Tip
Whenever you see a question involving frequency and period, just remember the simple rule: "Period is the reciprocal of frequency." If you are given a frequency of 50Hz, the period is $1/50 = 0.02\text{s}$ . If you are given a frequency of 100Hz, it is $1/100 = 0.01\text{s}$ . This is a very common JAMB question, so keep this relationship at your fingertips!
AI can make mistakes. Report anything that looks wrong.
43.
Heat transfer in the surrounding without a material medium is possible through?
1. A.Conduction
2. B.Convection
3. C.Radiation
4. D.Expansion
Show answer
Answer: C. Radiation
AI explanation
Analysis
The question asks for the method of heat transfer that does not require a material medium (like air, water, or metal) to travel through space or the surroundings.
Concept Explanation
Heat transfer occurs through three primary mechanisms:
Conduction: This is the transfer of heat through direct contact between particles of a solid. It requires a material medium.
Convection: This is the transfer of heat through the actual movement of fluid particles (liquids or gases). It also requires a material medium.
Radiation: This is the transfer of heat in the form of electromagnetic waves (specifically infrared waves). Unlike conduction and convection, radiation does not require any material medium to propagate. This is how heat from the Sun reaches the Earth through the vacuum of space.
Expansion: This is a physical change in the dimensions of a substance due to heat; it is not a method of heat transfer.
Step-by-Step Solution
Step 1: Evaluate the options based on the requirement of a "material medium."
Step 2: Conduction (A) and Convection (B) are ruled out because they rely on the vibration or movement of atoms/molecules within a substance.
Step 3: Expansion (D) is a result of heating, not a process of transferring heat from one place to another.
Step 4: Radiation (C) involves electromagnetic waves that can travel through a vacuum (the absence of a medium). Therefore, it is the only process that fits the criteria.
Conclusion
Exam Tip: Remember the "Three C's and an R": Conduction (needs contact), Convection (needs currents in fluids), and Radiation (needs no medium). If you see "vacuum" or "no medium" in a JAMB question, always look for Radiation.
AI can make mistakes. Report anything that looks wrong.
44.
Lodestone is a natural magnet, it points at
1. A.N – W when suspended freely
2. B.N–S when suspended freely
3. C.S – E when suspended freely
4. D.S–W when suspended freely
Show answer
Answer: B. N–S when suspended freely
Get a step-by-step AI explanation in the app Get a step-by-step AI explanation in the app
45.
Radio waves belong to the class of wave whose velocity is about
1. A.34m/s
2. B.3 ×106m/s
3. C.3 ×108m/s
4. D.3 × 10-8m/s
Show answer
Answer: C. 3 ×108m/s
Get a step-by-step AI explanation in the app Get a step-by-step AI explanation in the app
46.
Which of the following is not luminous object?
1. A.The sun
2. B.The moon
3. C.light candle
4. D.Star
Show answer
Answer: B. The moon
Get a step-by-step AI explanation in the app Get a step-by-step AI explanation in the app
47.
Heat transfer by convection will take place in one the following substance.
1. A.Stone
2. B.Wood
3. C.Mercury
4. D.Water
Show answer
Answer: D. Water
AI explanation
1. Analyze the Question
The question asks you to identify which of the listed substances allows for heat transfer via convection. To answer this, we must understand the physical requirements for convection to occur.
2. Explain the Concept
Convection is the transfer of heat through the actual movement of particles within a fluid.
What is a fluid? In physics, a fluid is any substance that can flow, which includes both liquids and gases.
How it works: When a fluid is heated, the molecules gain kinetic energy, move further apart, and become less dense. This warmer, less dense fluid rises, while cooler, denser fluid sinks to take its place, creating a "convection current."
Why not solids? Solids (like stone and wood) have a fixed structure. Heat transfer in solids occurs primarily through conduction, where energy is passed from atom to atom through vibration, without the atoms themselves moving from one place to another.
3. Show the Solution
Let's evaluate the options:
A. Stone: This is a solid. Heat transfer occurs via conduction.
B. Wood: This is a solid. Heat transfer occurs via conduction.
C. Mercury: While mercury is a liquid metal, it is a very good conductor of heat. In most standard physics contexts, heat transfer in metals (even liquid ones) is dominated by conduction due to the presence of free electrons.
D. Water: Water is a fluid (liquid). When heated, it easily forms convection currents, making it the classic example of heat transfer by convection.
4. Identify the Answer
Comparing the options, Water is the most appropriate substance for convection. While mercury is a liquid, its metallic nature makes conduction its primary mode of heat transfer, whereas water is the standard example of a substance that transfers heat primarily through convection.
5. Exam Tip
Memory Trick: Remember the "Fluid Rule." If it can flow (liquid or gas), it can undergo convection. If it is a solid, think conduction. If it can travel through a vacuum (like sunlight), think radiation!
AI can make mistakes. Report anything that looks wrong.
48.
A structural engineer stood on a top of a building releasing a light and heavy object to the ground which of the following statement is true?(Neglect Air Resistance)
1. A.Both the light and heavy subject reach the ground at the same time
2. B.The light object get to the ground first before the heavy object
3. C.The heavy object to the ground first before the light object
4. D.None get to the ground first
Show answer
Answer: A. Both the light and heavy subject reach the ground at the same time
AI explanation
1. Analyze the question
The question asks us to compare the time it takes for two objects of different masses (one light, one heavy) to fall from the same height to the ground, assuming air resistance is neglected.
2. Explain the concept
This is a classic problem in kinematics based on Galileo’s Law of Falling Bodies.
When air resistance is neglected, all objects fall towards the Earth with the same constant acceleration, known as the acceleration due to gravity ( $g$ ), which is approximately $9.8 \, \text{m/s}^2$ .
The equation of motion for an object falling from rest is:
$h = ut + \frac{1}{2}gt^2$
Since the objects are released from rest, the initial velocity ( $u$ ) is $0$ . The equation simplifies to:
$h = \frac{1}{2}gt^2$
Rearranging to solve for time ( $t$ ):
$t = \sqrt{\frac{2h}{g}}$
Notice that the mass of the object does not appear in this formula. This means the time taken to fall depends only on the height ( $h$ ) and the acceleration due to gravity ( $g$ ), not on the mass of the object.
3. Show the solution
Step 1: Identify the variables. Both objects are dropped from the same height ( $h$ ).
Step 2: Recognize that the acceleration due to gravity ( $g$ ) acts equally on all objects regardless of their mass.
Step 3: Apply the formula $t = \sqrt{\frac{2h}{g}}$ . Since $h$ and $g$ are the same for both objects, the time ( $t$ ) must be the same for both.
Conclusion: Because mass is not a factor in the absence of air resistance, both the light and heavy objects will hit the ground simultaneously.
4. Identify the answer
The correct statement is that both objects reach the ground at the same time. This corresponds to option A.
5. Exam Tip
Always remember: In a vacuum (or when air resistance is neglected), a feather and a hammer fall at the same rate. If you see a question about falling bodies in JAMB, check if air resistance is mentioned. If it is neglected, mass is irrelevant!
AI can make mistakes. Report anything that looks wrong.
49.
A vector quantity can only be completely described when ……… and …………are mentioned.
1. A.Magnitude and motion
2. B.Magnitude and direction
3. C.Distance and specified displacement
4. D.Moment and momentum
Show answer
Answer: B. Magnitude and direction
AI explanation
1. Analyze the question
The question asks for the two essential components required to fully define a vector quantity in physics.
2. Explain the concept
In physics, physical quantities are categorized into two main types:
Scalar Quantities: These are quantities that have only magnitude (size or numerical value) but no direction. Examples include distance, speed, mass, and time.
Vector Quantities: These are quantities that require both magnitude and direction to be fully described. If you only provide the magnitude, the description is incomplete. For example, if you say "a car is moving at 50 km/h," you have given the speed (scalar). If you say "a car is moving at 50 km/h due North," you have given the velocity (vector).
3. Show the solution
Option A (Magnitude and motion): "Motion" is a general term for change in position, not a specific requirement for defining a vector.
Option B (Magnitude and direction): This matches the definition of a vector quantity perfectly. A vector needs a value (magnitude) and a path/orientation (direction).
Option C (Distance and specified displacement): Distance is a scalar, and displacement is a vector. This does not define a vector quantity in general.
Option D (Moment and momentum): These are both examples of vector quantities, not the components required to define them.
4. Identify the answer
The correct option is B.
5. Exam Tip
To remember the difference, use the acronym "SMAD":
Scalar = Magnitude
Vector = Magnitude + Direction
Whenever you see a question about vectors, immediately look for the pair "Magnitude and Direction." If you see them together, that is almost certainly your answer!
AI can make mistakes. Report anything that looks wrong.
50.
Momentum and Kinetic energy are conserved in
1. A.Inelastic collision
2. B.Elastic collision
3. C.Explosion
4. D.Spacecraft
Show answer
Answer: B. Elastic collision
Get a step-by-step AI explanation in the app Get a step-by-step AI explanation in the app
51.
Calculate the gravitation force of attraction between two planets of $10^{24}$ kg and $10^{27}$ kg separated by a distance of $10^{20}$ meters
1. A.6.67N
2. B.6.56N
3. C.7.5N
4. D.8.6N
Show answer
Answer: A. 6.67N
Get a step-by-step AI explanation in the app Get a step-by-step AI explanation in the app
52.
If a projectile has maximum range of 36m, find the speed of projection (Take g = 9.8m/s2)
1. A.19m/s
2. B.2m/s
3. C.4m/s2
4. D.7m/s2
Show answer
Answer: A. 19m/s
AI explanation
1. Analyze the Question
We are given the maximum range ( $R_{max}$ ) of a projectile as 36m and the acceleration due to gravity ( $g$ ) as $9.8 \, \text{m/s}^2$ . We need to calculate the initial speed of projection ( $u$ ).
2. Explain the Concept
The range of a projectile is given by the formula:
$R = \frac{u^2 \sin(2\theta)}{g}$
For a projectile to achieve its maximum range, the angle of projection ( $\theta$ ) must be $45^\circ$ . Since $\sin(2 \times 45^\circ) = \sin(90^\circ) = 1$ , the formula for maximum range simplifies to:
$R_{max} = \frac{u^2}{g}$
3. Show the Solution
Step 1: State the formula for maximum range. $ $R_{max} = \frac{u^2}{g}$ $
Step 2: Substitute the given values into the formula. $ $36 = \frac{u^2}{9.8}$ $
Step 3: Solve for $u^2$ . $ $u^2 = 36 \times 9.8$ $ $ $u^2 = 352.8$ $
Step 4: Find the square root to get $u$ . $ $u = \sqrt{352.8}$ $ $ $u \approx 18.78 \, \text{m/s}$ $
Rounding this value to the nearest whole number gives us 19 m/s.
4. Identify the Answer
Comparing our result ( $18.78 \, \text{m/s}$ ) to the provided options, it aligns with option A.
Note: Options C and D are incorrect because they provide units for acceleration ( $\text{m/s}^2$ ) rather than speed ( $\text{m/s}$ ).
5. Exam Tip
Always check the units in your options! If a question asks for "speed," the answer must be in $\text{m/s}$ . If you see options with $\text{m/s}^2$ , you can immediately eliminate them as they represent acceleration, not speed. This is a quick way to narrow down your choices in JAMB.
AI can make mistakes. Report anything that looks wrong.
53.
A zinc has a heat capacity of 40 J/K, what is the mass of the zinc, given that the specific heat of zinc is 380 J/kg k
1. A.0.11kg
2. B.0.12kg
3. C.0.13kg
4. D.0.14kg
Show answer
Answer: A. 0.11kg
AI explanation
Analysis
To solve this problem, we need to understand the relationship between Heat Capacity and Specific Heat Capacity.
Heat Capacity ( $C$ ): The amount of heat required to raise the temperature of the entire body by 1 Kelvin. Its unit is $J/K$ .
Specific Heat Capacity ( $c$ ): The amount of heat required to raise the temperature of unit mass (1kg) of a substance by 1 Kelvin. Its unit is $J/kg \cdot K$ .
Concept
The formula connecting these two is:
$C = m \times c$
Where:
$C$ = Heat Capacity ( $40 \, J/K$ )
$m$ = Mass ( $kg$ )
$c$ = Specific Heat Capacity ( $380 \, J/kg \cdot K$ )
Solution
Rearrange the formula to solve for mass ( $m$ ): $ $m = \frac{C}{c}$ $
Substitute the given values into the equation: $ $m = \frac{40}{380}$ $
Calculate the result: $ $m = \frac{4}{38}$ $ $ $m \approx 0.10526... \, kg$ $
Rounding: Rounding $0.10526$ to two decimal places gives us $0.11 \, kg$ .
Conclusion
Comparing our result to the provided options, $0.11 \, kg$ matches option A.
Exam Tip
Always check your units before calculating! If the specific heat capacity were given in $J/g \cdot K$ instead of $J/kg \cdot K$ , you would have had to convert the mass units accordingly. In JAMB Physics, always ensure your mass is in kilograms (kg) when working with standard SI units.
AI can make mistakes. Report anything that looks wrong.
54.
The compressed regions and the space-out regions in longitude wave are refers to as
1. A.Compression and Rarefaction
2. B.Comparison and Explosion
3. C.Reflection only
4. D.Refraction only
Show answer
Answer: A. Compression and Rarefaction
AI explanation
1. Analyze the question
The question asks for the specific terminology used to describe the two alternating regions found in a longitudinal wave: the area where particles are pushed together (compressed) and the area where they are spread apart.
2. Explain the concept
A longitudinal wave is a wave in which the particles of the medium vibrate parallel to the direction of wave propagation (e.g., sound waves).
Compression: This is the region in a longitudinal wave where the particles of the medium are crowded or packed closely together, resulting in high pressure and high density.
Rarefaction: This is the region where the particles are spread out or far apart, resulting in low pressure and low density.
3. Show the solution
The "compressed regions" mentioned in the question are scientifically referred to as Compressions.
The "space-out regions" (or stretched-out regions) are scientifically referred to as Rarefactions.
Looking at the options provided:
Option A matches these definitions perfectly.
Options B, C, and D use terms that are either unrelated to the structure of longitudinal waves or refer to wave behaviors (like reflection and refraction) rather than the regions of the wave itself.
4. Identify the answer
The correct terminology for the compressed and spaced-out regions is Compression and Rarefaction.
5. Tip
Think of a Slinky spring: when you push it forward, the coils bunch up (Compression), and when you pull it back, the coils stretch out (Rarefaction). Remember: Compression = Crowded, Rarefaction = Relaxed/Spread out.
AI can make mistakes. Report anything that looks wrong.
55.
Convert 45°C to kelvin
1. A.318K
2. B.250K
3. C.184K
4. D.120K
Show answer
Answer: A. 318K
AI explanation
Analysis
The question asks for the conversion of a temperature value from the Celsius scale (°C) to the Kelvin scale (K). This is a fundamental concept in thermodynamics often tested in JAMB Physics.
Concept
The relationship between the Celsius scale and the Kelvin scale is defined by the formula:
$T(K) = \theta(°C) + 273.15$
In most JAMB and secondary school examinations, the value 273 is used as the standard constant for this conversion. Therefore, the simplified formula is:
$T(K) = \theta(°C) + 273$
Solution
Identify the given value: $\theta = 45°C$
Apply the formula: $T(K) = 45 + 273$
Perform the addition: $45 + 273 = 318$
So, 45°C is equivalent to 318K.
Conclusion
Comparing our result to the provided options: A. 318K B. 250K C. 184K D. 120K
The correct option is A.
Exam Tip
Always remember: "Celsius to Kelvin, add 273; Kelvin to Celsius, subtract 273." A common mistake students make is subtracting when they should be adding. Since the Kelvin scale starts at absolute zero (-273°C), the Kelvin value will almost always be higher than the Celsius value for temperatures above absolute zero.
AI can make mistakes. Report anything that looks wrong.
56.
In an inelastic collision I. Energy is conserved II. Energy is decreased III. Energy is increased IV. Linear momentum conserved
1. A.I only
2. B.II and IV only
3. C.II only
4. D.III only
Show answer
Answer: B. II and IV only
AI explanation
Analysis of the Question
This question tests your understanding of the laws of conservation in physics, specifically regarding collisions. You need to distinguish between elastic and inelastic collisions.
Concept Explanation
Linear Momentum: According to the Law of Conservation of Linear Momentum, the total momentum of a system remains constant in any collision (whether elastic or inelastic), provided no external force acts on the system.
Kinetic Energy: • In an elastic collision, both linear momentum and kinetic energy are conserved. • In an inelastic collision, linear momentum is conserved, but kinetic energy is not conserved. Instead, some of the kinetic energy is transformed into other forms of energy (such as heat, sound, or deformation energy). Therefore, the total kinetic energy of the system decreases after the collision.
Step-by-Step Solution
Step 1: Evaluate Statement I ("Energy is conserved"). This is false for inelastic collisions because kinetic energy is lost to other forms.
Step 2: Evaluate Statement II ("Energy is decreased"). This is true. In an inelastic collision, the total kinetic energy after the collision is less than the total kinetic energy before the collision.
Step 3: Evaluate Statement III ("Energy is increased"). This is false. Energy is not created during a collision; it is only transformed or dissipated.
Step 4: Evaluate Statement IV ("Linear momentum conserved"). This is true. The principle of conservation of momentum applies to all collisions.
Combining these, statements II and IV are the correct descriptions of an inelastic collision.
Conclusion
Based on the analysis, the correct statements are II and IV. This corresponds to option B.
Exam Tip: Always remember the "Golden Rule" of collisions: Momentum is always conserved, but Kinetic Energy is only conserved in elastic collisions. If you see the word "inelastic," immediately look for the option that mentions a decrease in energy!
AI can make mistakes. Report anything that looks wrong.
57.
The general gas law can be written as
1. A.PV ÷ T = a constant
2. B.PV = a constant
3. C.v/t = a constant
4. D.p/T = a constant
Show answer
Answer: A. PV ÷ T = a constant
Get a step-by-step AI explanation in the app Get a step-by-step AI explanation in the app
58.
What is the S.I unit of relative density?
1. A.kg m-2
2. B.kg m2
3. C.kg cm3
4. D.has no S.I unit
Show answer
Answer: D. has no S.I unit
AI explanation
1. Analyze the question
The question asks for the S.I. unit of relative density. To answer this, we need to understand what relative density represents physically and how it is calculated.
2. Explain the concept
Relative density (also known as specific gravity) is defined as the ratio of the density of a substance to the density of a standard substance (usually water at 4°C).
The formula is:
$\text{Relative Density} = \frac{\text{Density of substance}}{\text{Density of water}}$
Since density is measured in $\text{kg/m}^3$ (or $\text{g/cm}^3$ ), the calculation looks like this:
$\text{Relative Density} = \frac{\text{kg/m}^3}{\text{kg/m}^3}$
Because the units in the numerator and the denominator are identical, they cancel each other out completely.
3. Show the solution
Step 1: Identify the units of the numerator: $\text{kg/m}^3$ .
Step 2: Identify the units of the denominator: $\text{kg/m}^3$ .
Step 3: Perform the division: $\frac{\text{kg/m}^3}{\text{kg/m}^3} = 1$ .
Step 4: Since the units cancel out, the resulting value is a dimensionless quantity. A dimensionless quantity has no unit.
4. Identify the answer
Because relative density is a ratio of two similar physical quantities, it does not have an S.I. unit. Looking at the options provided, option D correctly states this.
5. Exam Tip
Whenever you encounter a physics term that is defined as a "ratio" (like Relative Density, Refractive Index, or Strain), remember that these quantities are dimensionless. They will never have an S.I. unit. This is a common "trick" question in JAMB to test if you understand the definition of physical quantities rather than just memorizing formulas.
AI can make mistakes. Report anything that looks wrong.
59.
The external parts of an object can be measure accurately through the use of which scientific instrument?
1. A.Micrometer screw gauge
2. B.Vernier Caliper
3. C.Meter rule
4. D.None of the instrument
Show answer
Answer: B. Vernier Caliper
AI explanation
1. Analyze the question
The question asks for the specific scientific instrument used to measure the external dimensions (such as the diameter or thickness) of an object with high accuracy.
2. Explain the concept
In physics, different instruments are used for different levels of precision:
Meter rule: Used for general measurements where precision to the nearest millimeter (0.1 cm) is sufficient.
Vernier Caliper: Designed specifically to measure the internal and external diameters of objects, as well as depths. It provides a higher degree of accuracy than a meter rule (typically up to 0.01 cm or 0.1 mm).
Micrometer screw gauge: Used for extremely small measurements (like the thickness of a wire or a thin sheet of metal) with even higher precision (up to 0.001 cm or 0.01 mm).
While both the Vernier Caliper and the Micrometer screw gauge are accurate, the Vernier Caliper is the standard instrument taught in the Nigerian secondary school curriculum for measuring the external dimensions of objects like cylinders, spheres, or blocks.
3. Show the solution
Step 1: Evaluate the options based on the required precision for "external parts."
Step 2: A meter rule is too imprecise for specialized external measurements.
Step 3: A Micrometer screw gauge is generally reserved for very small, thin objects (like the diameter of a thin wire).
Step 4: The Vernier Caliper is the most versatile and commonly used tool for measuring the external dimensions of solid objects in a laboratory setting.
4. Identify the answer
The Vernier Caliper is the standard instrument for measuring external dimensions accurately in this context.
5. Tip
Memory Trick: Remember the "V" in Vernier for "Versatile." It is the most versatile tool for measuring external, internal, and depth dimensions. If the question specifically mentions a "thin wire" or "very small thickness," lean toward the Micrometer screw gauge; for general external dimensions of objects, choose the Vernier Caliper.
AI can make mistakes. Report anything that looks wrong.
60.
What type of electromagnetic radiation can be used to take photographs in the haze?
1. A.Radio waves
2. B.infrared rays
3. C.Visible light
4. D.Gamma rays
Show answer
Answer: B. infrared rays
AI explanation
1. Analyze the question
The question asks for the specific type of electromagnetic radiation capable of penetrating "haze" (or fog/mist) to capture clear photographs. This is a common application of electromagnetic waves in photography and surveillance.
2. Explain the concept
Electromagnetic radiation is categorized by wavelength and frequency. Different types of radiation interact with matter (like water droplets in haze or fog) in different ways:
Visible light: Has shorter wavelengths that are easily scattered by small particles like water droplets in haze, which is why visibility is poor in foggy conditions.
Infrared rays: These have longer wavelengths than visible light. Because of their longer wavelength, they are not easily scattered by the small particles that make up haze or fog. This allows them to pass through the haze and reach a sensor or film, making them ideal for "haze-penetration" photography.
3. Show the solution
Step 1: Evaluate the options based on their ability to penetrate atmospheric particles.
Step 2: Radio waves have very long wavelengths but are not used for standard photography.
Step 3: Visible light is scattered by haze, which is why we cannot see clearly through it with the naked eye.
Step 4: Gamma rays have extremely short wavelengths and high energy; they are absorbed by the atmosphere and are not used for landscape or haze photography.
Step 5: Infrared radiation is specifically used in specialized photography (often called "infrared photography") because it can penetrate atmospheric haze, smoke, and fog better than visible light.
4. Identify the answer
Based on the properties of electromagnetic waves, infrared rays are the correct choice for taking photographs in the haze.
5. Tip
Memory Trick: Remember the acronym "IR = Infrared = Invisible/In-haze". Whenever you see questions about "haze," "fog," or "night vision" in physics, think of Infrared.
AI can make mistakes. Report anything that looks wrong.
61.
Boyle’s law may be Written as
1. A.P1V1= P2V2
2. B.V1 = V2 ÷ T1T2
3. C.P1T1 = P2T2
4. D.P1V1 ÷ T1 = P1V1 ÷ T2
Show answer
Answer: A. P1V1= P2V2
AI explanation
Analysis
The question asks for the mathematical representation of Boyle’s Law, which describes the relationship between the pressure and volume of a fixed mass of gas at a constant temperature.
Concept: Boyle’s Law
Boyle’s Law states that for a fixed mass of an ideal gas, the pressure ( $P$ ) is inversely proportional to its volume ( $V$ ), provided the temperature ( $T$ ) remains constant.
Mathematically, this is expressed as: $P \propto \frac{1}{V}$ Which leads to the equation: $PV = k$ (where $k$ is a constant)
When comparing the same gas under two different sets of conditions (state 1 and state 2) at a constant temperature, we equate the constants: $P_1V_1 = P_2V_2$
Step-by-Step Solution
Identify the variables: $P$ represents Pressure, $V$ represents Volume.
Apply the condition: The law specifies that temperature must be constant.
Formulate the relationship: Since $P$ is inversely proportional to $V$ , the product of pressure and volume remains constant ( $PV = \text{constant}$ ).
Compare states: If the initial state is $(P_1, V_1)$ and the final state is $(P_2, V_2)$ , then: $P_1V_1 = P_2V_2$
Reviewing the Options
A. $P_1V_1 = P_2V_2$ : This correctly represents Boyle's Law.
B. $V_1 = V_2 \div T_1T_2$ : This is incorrect and does not represent any standard gas law.
C. $P_1T_1 = P_2T_2$ : This is incorrect; it resembles a variation of Gay-Lussac's Law, but is written incorrectly.
D. $P_1V_1 \div T_1 = P_1V_1 \div T_2$ : This is a distorted version of the General Gas Law (Combined Gas Law).
Exam Tip
To remember the gas laws easily, use the mnemonic "TV-PU-PT":
T (Temperature) is constant for Boyle's Law ( $PV = k$ ).
V (Volume) is constant for Pressure Law ( $P/T = k$ ).
P (Pressure) is constant for Charles's Law ( $V/T = k$ ).
AI can make mistakes. Report anything that looks wrong.
62.
If a ball released from a height of 20m, How long would it take the ball to reach the ground? (assures g = 10m/s)
1. A.2sec
2. B.3sec
3. C.35sec
4. D.2.4sec
Show answer
Answer: A. 2sec
AI explanation
1. Analyze the question
We are given the height ( $h$ ) from which a ball is dropped and the acceleration due to gravity ( $g$ ). We need to find the time ( $t$ ) it takes for the ball to hit the ground.
Height ( $h$ ) = 20 m
Acceleration due to gravity ( $g$ ) = 10 m/s²
Initial velocity ( $u$ ) = 0 m/s (since the ball is "released" or dropped)
2. Explain the concept
This is a problem involving equations of motion under gravity. When an object is dropped from rest, we use the second equation of motion:
$h = ut + \frac{1}{2}gt^2$
Since the initial velocity ( $u$ ) is 0, the equation simplifies to:
$h = \frac{1}{2}gt^2$
3. Show the solution
Step 1: Substitute the known values into the simplified formula.
$20 = \frac{1}{2} \times 10 \times t^2$
Step 2: Simplify the right side of the equation.
$20 = 5 \times t^2$
Step 3: Solve for $t^2$ by dividing both sides by 5.
$t^2 = \frac{20}{5}$
$t^2 = 4$
Step 4: Take the square root of both sides to find $t$ .
$t = \sqrt{4}$
$t = 2 \text{ seconds}$
4. Identify the answer
Comparing our result to the given options: A. 2sec B. 3sec C. 35sec D. 2.4sec
The correct option is A.
5. Tip
Whenever you see a question about an object being "dropped" or "released," always remember that the initial velocity ( $u$ ) is zero. This makes your calculation much faster because the $ut$ part of the equation disappears! Also, always ensure your units are consistent (meters and seconds) before you start calculating.
AI can make mistakes. Report anything that looks wrong.
63.
When a man moves toward a plane mirror at a speed of 6m/s, the distance the man and his image increased at a speed of?
1. A.2 m/s
2. B.4 m/s
3. C.12 m/s
4. D.14 m/s
Show answer
Answer: C. 12 m/s
Get a step-by-step AI explanation in the app Get a step-by-step AI explanation in the app
64.
If the volume of a gas is recorded as 76cm3 at a temperature of 27°C with a pressure of 800mmHg. What will be the volume of the gas at S.T.P?
1. A.36.2cm3
2. B.25.7cm3
3. C.72.8cm3
4. D.24.3cm3
Show answer
Answer: C. 72.8cm3
Get a step-by-step AI explanation in the app Get a step-by-step AI explanation in the app
65.
A regular spacing or arrangement of atoms in a crystalline material is called
1. A.Orbit
2. B.Lattice
3. C.Atomic structure
4. D.Energy level
Show answer
Answer: B. Lattice
AI explanation
1. Analyze the question
The question asks for the specific scientific term used to describe the orderly, repeating, three-dimensional arrangement of atoms or molecules within a crystalline solid.
2. Explain the concept
In solid-state physics and chemistry, materials are classified based on how their atoms are arranged:
Amorphous solids: Atoms are arranged randomly (like glass).
Crystalline solids: Atoms are arranged in a highly ordered, repeating pattern that extends in all three spatial dimensions. This geometric arrangement is referred to as a crystal lattice.
3. Show the solution
Option A (Orbit): This refers to the path an electron takes around the nucleus of an atom. It is not related to the arrangement of atoms in a solid.
Option B (Lattice): This is the correct term for the regular, repeating geometric arrangement of points (atoms, ions, or molecules) in a crystal.
Option C (Atomic structure): This is a broad term describing the composition of an atom (protons, neutrons, and electrons), not the arrangement of atoms in a material.
Option D (Energy level): This refers to the specific quantized energy states that electrons can occupy within an atom.
Since the question specifically asks for the "regular spacing or arrangement of atoms," the term that fits this definition is Lattice.
4. Identify the answer
The correct option is B.
5. Tip
Think of a "lattice" like a garden trellis or a wire mesh fence—it has a repeating, structured pattern. In physics, whenever you see the phrase "regular arrangement of atoms" in a crystal, immediately look for the word "Lattice."
AI can make mistakes. Report anything that looks wrong.

2015 JAMB Physics Past Questions

Questions

1. Analyze the question

2. Explain the concept

3. Show the solution

4. Identify the answer

5. Tip

Analysis

Concept Explanation

Step-by-Step Solution

Answer

Exam Tip

1. Analyze the question

2. Explain the concept

3. Show the solution

4. Identify the answer

5. Exam Tip

Analysis of the Question

Concept Explanation

Step-by-Step Solution

Conclusion

1. Analyze the Question

2. Explain the Concept

3. Show the Solution

4. Identify the Answer

5. Exam Tip

Analysis

Explanation

Step-by-Step Solution

Conclusion

Exam Tip

Analysis

Concept Explanation

Step-by-Step Solution

Exam Tip

Analysis

Concept Explanation

Step-by-Step Solution

Exam Tip

Analysis of the Question

Concept Explanation

Step-by-Step Solution

Conclusion

Analysis

Concept Explanation

Step-by-Step Solution

Exam Tip

Analysis of the Question

Concept Explanation

Step-by-Step Solution

Conclusion

1. Analyze the question

2. Explain the concept

3. Show the solution

4. Identify the answer

5. Tip

1. Analyze the question

2. Explain the concept

3. Show the solution

4. Identify the answer

5. Tip

Analysis of the Question

Explanation of the Concept

Step-by-Step Solution

Conclusion

Analysis

Concept Explanation

Step-by-Step Solution

Identifying the Answer

Exam Tip

1. Analyze the question

2. Explain the concept

3. Show the solution

4. Identify the answer

5. Tip

Analysis

Concept Explanation

Step-by-Step Solution

Conclusion

Analysis of the Question