DeeepSolve Logo
DeeepSolve
Get app
JAMB 2017

2017 JAMB Physics Past Questions

The 2017 JAMB Physics past questions with answers: 49 objective questions from the 2017 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.

Past questions © the examination body (JAMB/WAEC/NECO). DeeepSolve is not affiliated with them. Rights holders: see /copyright.

Questions

  1. 1.

    Calculate the specific latent heat of vaporization of steam of 1.13 x 106J of heat energy is required to convert 15kg of steam to water.

    1. A.7.53 x 105 Jkg−1^{-1}
    2. B.7.53 x 10-2Jkg−1^{-1}
    3. C.7.53×1047.53 \times 10^{4}Jkg−1^{-1}
    4. D.7.53 x 10-3Jkg−1^{-1}
    Show answer

    Answer: C. 7.53×1047.53 \times 10^{4}Jkg−1^{-1}

    AI explanation

    1. Analyze the question

    We are given the total heat energy (QQ) required to change the state of a substance and the mass (mm) of that substance. We need to find the specific latent heat of vaporization (LvL_v).

    • Heat energy (QQ): 1.13×106 J1.13 \times 10^6 \text{ J}
    • Mass (mm): 15 kg15 \text{ kg}
    • Specific latent heat (LvL_v): ?
    2. Explain the concept

    The specific latent heat of vaporization is the amount of heat energy required to change a unit mass of a substance from liquid to gas (or vice versa) at a constant temperature. The formula is:

    Q=mLvQ = mL_v

    To find LvL_v, we rearrange the formula:

    Lv=QmL_v = \frac{Q}{m}
    3. Show the solution

    Substitute the given values into the formula:

    Lv=1.13×106 J15 kgL_v = \frac{1.13 \times 10^6 \text{ J}}{15 \text{ kg}}

    First, perform the division:

    1.13÷15≈0.075333...1.13 \div 15 \approx 0.075333...

    Now, combine this with the power of 10:

    Lv=0.07533×106 Jkg−1L_v = 0.07533 \times 10^6 \text{ Jkg}^{-1}

    To express this in standard form (scientific notation), move the decimal point two places to the right:

    Lv=7.53×10−2×106 Jkg−1L_v = 7.53 \times 10^{-2} \times 10^6 \text{ Jkg}^{-1}
    Lv=7.53×104 Jkg−1L_v = 7.53 \times 10^4 \text{ Jkg}^{-1}
    4. Identify the answer

    Comparing our result to the options provided: A. 7.53×105 Jkg−17.53 \times 10^5 \text{ Jkg}^{-1} B. 7.53×10−2 Jkg−17.53 \times 10^{-2} \text{ Jkg}^{-1} C. 7.53×104 Jkg−17.53 \times 10^4 \text{ Jkg}^{-1} D. 7.53×10−3 Jkg−17.53 \times 10^{-3} \text{ Jkg}^{-1}

    The calculated value matches Option C.

    5. Tip

    When dealing with scientific notation in JAMB physics, always check the powers of 10 carefully. A common mistake is miscounting the decimal shift. Remember: moving the decimal to the right decreases the exponent, and moving it to the left increases it. You've got this!

    AI can make mistakes. Report anything that looks wrong.

  2. 2.

    When the r.m.s value of a source of electricity supply is given as 240v, it means that the peak value of the supply is

    1. A.240v
    2. B.340v
    3. C.480v
    4. D.57600v
    Show answer

    Answer: B. 340v

    Get a step-by-step AI explanation in the app

  3. 3.

    Calculate the electric field intensity between two plates of potential difference 6.5V when separated by a distance of 35cm.

    1. A.18.57NC−1^{-1}
    2. B.53.06N C−1^{-1}
    3. C.2.28NC−1^{-1}
    4. D.0.80NC−1^{-1}
    Show answer

    Answer: A. 18.57NC−1^{-1}

    Get a step-by-step AI explanation in the app

  4. 4.This question needs a diagram, table or passage that we don't have yet, so it isn't shown.

  5. 5.

    Which of the following is not an electromagnetic radiation?

    1. A.x - ray
    2. B.Radio waves
    3. C.sunlight
    4. D.sound waves
    Show answer

    Answer: D. sound waves

    AI explanation

    Analysis

    The question asks us to identify which of the listed options does not belong to the electromagnetic spectrum. To solve this, we must distinguish between electromagnetic waves and mechanical waves.

    Concept Explanation

    Electromagnetic (EM) radiation consists of waves that do not require a material medium to propagate; they can travel through a vacuum (like space). They are produced by the oscillation of electric and magnetic fields. Common examples include:

    • Radio waves
    • Microwaves
    • Infrared radiation
    • Visible light (sunlight)
    • Ultraviolet rays
    • X-rays
    • Gamma rays

    Mechanical waves, on the other hand, require a material medium (solid, liquid, or gas) to travel. They cannot travel through a vacuum. Sound waves are the most common example of mechanical waves because they rely on the vibration of particles in a medium to transfer energy.

    Step-by-Step Solution
    1. Evaluate Option A (X-rays): X-rays are high-frequency electromagnetic waves. They are part of the EM spectrum.
    2. Evaluate Option B (Radio waves): Radio waves are low-frequency electromagnetic waves used for communication. They are part of the EM spectrum.
    3. Evaluate Option C (Sunlight): Sunlight is composed of visible light, which is the portion of the electromagnetic spectrum that the human eye can detect. It is electromagnetic radiation.
    4. Evaluate Option D (Sound waves): Sound waves are longitudinal mechanical waves. They require a medium like air, water, or steel to travel. They are not electromagnetic.
    Conclusion

    Since sound waves require a medium and do not consist of oscillating electric and magnetic fields, they are the only option listed that is not an electromagnetic radiation.

    Exam Tip: Remember the mnemonic "Raging Martians Invaded Venus Using X-ray Guns" to recall the EM spectrum in order of decreasing wavelength (Radio, Microwave, Infrared, Visible, Ultraviolet, X-ray, Gamma). Notice that "Sound" is never on this list!

    AI can make mistakes. Report anything that looks wrong.

  6. 6.

    Which of the following is correct about an electric cell?

    1. A.Primary cell produces a large current for a long time
    2. B.Secondary cell has a very high internal resistance
    3. C.Primary cell has a very low internal resistance
    4. D.Secondary cell has a very low internal resistance
    Show answer

    Answer: D. Secondary cell has a very low internal resistance

    AI explanation

    Analysis of the Question

    This question tests your understanding of the characteristics of electric cells, specifically the difference between primary cells and secondary cells in terms of their internal resistance and their ability to deliver current.

    Concept Explanation
    • Primary Cells: These are cells that cannot be recharged once they are exhausted (e.g., Leclanché cell, Daniell cell). They are generally designed for low-drain devices and typically have a high internal resistance, which limits the amount of current they can supply.
    • Secondary Cells (Accumulators): These are rechargeable cells (e.g., Lead-acid accumulator, Nickel-cadmium cell). They are designed to supply large currents for extended periods. To achieve this, they are constructed with a very low internal resistance. This low resistance allows them to deliver high current without a significant drop in terminal voltage.
    Step-by-Step Solution
    1. Evaluate Option A: Primary cells are usually for low-current applications (like remote controls or wall clocks). They do not produce large currents for long periods. This is incorrect.
    2. Evaluate Option B: Secondary cells are designed to provide high current, which is only possible if the internal resistance is low. Therefore, saying they have a "very high" internal resistance is incorrect.
    3. Evaluate Option C: Primary cells typically have a high internal resistance, not a low one. This is incorrect.
    4. Evaluate Option D: Because secondary cells are designed to deliver high currents (like starting a car engine), they must have a very low internal resistance to minimize energy loss within the cell and prevent overheating. This is the correct characteristic.
    Conclusion

    Exam Tip: Remember the "LR" rule for secondary cells: Low Resistance = Large Rechargeable current. This will help you recall that secondary cells are built for efficiency and high output!

    AI can make mistakes. Report anything that looks wrong.

  7. 7.

    It is known that a neutron exists in a light atomic nucleus Which of the following also exists in the nucleus?

    1. A.An electron
    2. B.A β - particle
    3. C.β - particle
    4. D.proton
    Show answer

    Answer: D. proton

    AI explanation

    Analysis of the Question

    The question asks for the fundamental subatomic particles that constitute the nucleus of a light atom. You are given that a neutron is present and need to identify the other particle that completes the composition of the nucleus.

    Concept Explanation

    According to the Rutherford-Bohr model of the atom:

    1. The Nucleus: This is the dense central core of an atom. It is composed of two primary types of nucleons: protons and neutrons.
    2. Protons: These are positively charged particles found inside the nucleus. The number of protons determines the atomic number of the element.
    3. Neutrons: These are neutral particles (no charge) also found inside the nucleus.
    4. Electrons: These are negatively charged particles that orbit the nucleus in specific energy levels or shells. They are not part of the nucleus.

    While β\beta-particles (beta particles) are high-energy electrons emitted during radioactive decay, they are not permanent structural components of a stable atomic nucleus.

    Step-by-Step Solution
    1. Identify the components: We know the nucleus contains nucleons. The two types of nucleons are protons and neutrons.
    2. Evaluate the options: • A (An electron): Incorrect. Electrons exist in shells outside the nucleus. • B & C (β\beta-particle): Incorrect. These are emitted during decay; they are not standard building blocks of the nucleus. • D (Proton): Correct. Protons and neutrons are the two particles that make up the nucleus of every atom (except for the simplest isotope of Hydrogen, which has only one proton).
    Conclusion

    The nucleus of an atom is composed of protons and neutrons. Since the question states that a neutron is present, the other particle that must be present is the proton.

    Exam Tip

    Remember the mnemonic "P-N" for the nucleus: Protons and Neutrons. If you ever get confused about where electrons are, remember they are the "orbiters" on the outside, while the heavy lifting (the mass of the atom) happens inside the nucleus with the protons and neutrons.

    AI can make mistakes. Report anything that looks wrong.

  8. 8.

    A constant force of 5N acts for 5 seconds on a mass of 5kg initially at rest. Calculate the final momentum

    1. A.125kgms−1
    2. B.25kgms−1
    3. C.15kgms−1
    4. D.0kgms−1
    Show answer

    Answer: B. 25kgms−1

    AI explanation

    1. Analyze the question

    We are given:

    • Force (FF) = 5 N5\text{ N}
    • Time (tt) = 5 s5\text{ s}
    • Mass (mm) = 5 kg5\text{ kg}
    • Initial velocity (uu) = 0 m/s0\text{ m/s} (since it is initially at rest)
    • We need to find the final momentum (pp).
    2. Explain the concept

    Momentum (pp) is defined as the product of mass and velocity (p=mvp = mv). According to Newton's Second Law of Motion, the rate of change of momentum is equal to the applied force. This is expressed by the Impulse-Momentum Theorem:

    Impulse=Change in Momentum\text{Impulse} = \text{Change in Momentum}
    Force×Time=m(v−u)\text{Force} \times \text{Time} = m(v - u)

    Since the object starts from rest (u=0u = 0), the final momentum is simply equal to the impulse applied to the object.

    3. Show the solution

    Step 1: Identify the formula for Impulse.

    Impulse=F×t\text{Impulse} = F \times t

    Step 2: Calculate the Impulse.

    Impulse=5 N×5 s=25 Ns\text{Impulse} = 5\text{ N} \times 5\text{ s} = 25\text{ Ns}

    Step 3: Relate Impulse to Momentum. Since Impulse = Change in Momentum (Δp\Delta p):

    Δp=pfinal−pinitial\Delta p = p_{\text{final}} - p_{\text{initial}}

    Because the object starts from rest, pinitial=m×0=0p_{\text{initial}} = m \times 0 = 0. Therefore:

    25 Ns=pfinal−025\text{ Ns} = p_{\text{final}} - 0
    pfinal=25 kgms−1p_{\text{final}} = 25\text{ kgms}^{-1}

    (Note: The unit of Impulse, Newton-seconds (Ns), is equivalent to the unit of momentum, kgms−1\text{kgms}^{-1}.)

    4. Identify the answer

    Comparing our result to the options provided: A. 125 kgms−1125\text{ kgms}^{-1} B. 25 kgms−125\text{ kgms}^{-1} C. 15 kgms−115\text{ kgms}^{-1} D. 0 kgms−10\text{ kgms}^{-1}

    The correct option is B.

    5. Tip

    Whenever you see a question involving "Force," "Time," and "Momentum," think of the word Impulse. Remember the acronym FIT: Force ×\times Impulse = Time (or more accurately, F×t=ΔpF \times t = \Delta p). This saves you the stress of calculating acceleration and final velocity separately!

    AI can make mistakes. Report anything that looks wrong.

  9. 9.

    Which of the following representations is correct for an atom X with 28 electrons and 30 neutrons?

    1. A.2858X^{58}_{28}X
    2. B.2830X^{30}_{28}X
    3. C.3028X^{28}_{30}X
    4. D.3058X^{58}_{30}X
    Show answer

    Answer: A. 2858X^{58}_{28}X

    Get a step-by-step AI explanation in the app

  10. 10.

    Which is the incorrect formula for a body accelerating uniformly?

    1. A.a = v2 − u22\frac{u^2}{2}
    2. B.v2 = u2 + 2as
    3. C.s = ut + 12\frac{1}{2} at2
    4. D.v2 − u2= 2as
    Show answer

    Answer: A. a = v2 − u22\frac{u^2}{2}

    AI explanation

    To identify the incorrect formula, we must look at the standard equations of uniformly accelerated motion (often called the equations of kinematics).

    1. Analyze the Concepts

    For a body moving with uniform acceleration (aa), initial velocity (uu), final velocity (vv), time (tt), and displacement (ss), the standard equations are:

    1. v=u+atv = u + at
    2. s=ut+12at2s = ut + \frac{1}{2}at^2
    3. v2=u2+2asv^2 = u^2 + 2as
    4. s=(u+v2)ts = (\frac{u + v}{2})t
    2. Evaluate the Options
    • Option B (v2=u2+2asv^2 = u^2 + 2as): This is a standard kinematic equation. It is correct.
    • Option C (s=ut+12at2s = ut + \frac{1}{2}at^2): This is the standard equation for displacement under uniform acceleration. It is correct.
    • Option D (v2−u2=2asv^2 - u^2 = 2as): If you rearrange Option B by subtracting u2u^2 from both sides, you get v2−u2=2asv^2 - u^2 = 2as. This is mathematically identical to Option B. It is correct.
    • Option A (a=v2−u22a = v^2 - \frac{u^2}{2}): Let's test the dimensions and the algebra. If we rearrange the correct equation v2=u2+2asv^2 = u^2 + 2as to solve for aa: v2−u2=2asv^2 - u^2 = 2as a=v2−u22sa = \frac{v^2 - u^2}{2s} Comparing this to Option A, we see that Option A is missing the displacement (ss) in the denominator and is dimensionally inconsistent. Therefore, it is the incorrect formula.
    3. Conclusion

    As shown in the derivation above, the acceleration aa must be divided by the displacement ss for the formula to be physically and mathematically correct.

    Exam Tip

    When dealing with kinematic equations in JAMB, always remember the "SUVAT" variables: S (displacement), U (initial velocity), V (final velocity), A (acceleration), and T (time). Every standard equation must contain a combination of these variables that is dimensionally consistent. If you see a formula missing a key variable like ss or tt where it should be, it is likely the "incorrect" one!

    AI can make mistakes. Report anything that looks wrong.

  11. 11.

    A cell of internal resistance 2Ω supplies current to a 6Ω resistor. The efficiency of the cell is

    1. A.12.0%
    2. B.25.0%
    3. C.33.3%
    4. D.75.0%
    Show answer

    Answer: D. 75.0%

    AI explanation

    1. Analyze the question

    We are given a cell with an internal resistance (rr) of 2Ω2\Omega connected to an external load resistor (RR) of 6Ω6\Omega. We need to calculate the efficiency of the cell.

    2. Explain the concept

    The efficiency (η\eta) of a cell is defined as the ratio of the useful power delivered to the external resistor to the total power generated by the cell.

    Mathematically, it is expressed as:

    η=Useful PowerTotal Power×100%\eta = \frac{\text{Useful Power}}{\text{Total Power}} \times 100\%

    Since Power P=I2RP = I^2R, we can write:

    η=I2RI2(R+r)×100%\eta = \frac{I^2R}{I^2(R + r)} \times 100\%

    By cancelling out the I2I^2 (current squared), the formula simplifies to:

    η=RR+r×100%\eta = \frac{R}{R + r} \times 100\%
    3. Show the solution
    • Step 1: Identify the given values • External resistance (RR) = 6Ω6\Omega • Internal resistance (rr) = 2Ω2\Omega
    • Step 2: Substitute the values into the formula $η=66+2×100%\eta = \frac{6}{6 + 2} \times 100\%$
    • Step 3: Perform the calculation $η=68×100%\eta = \frac{6}{8} \times 100\%$ $η=0.75×100%\eta = 0.75 \times 100\%$ $η=75.0%\eta = 75.0\%$
    4. Identify the answer

    Comparing our result to the given options, the correct choice is D.

    5. Exam Tip

    Whenever you see a question about the efficiency of a cell, remember the "Voltage Ratio" trick: Efficiency is simply the ratio of the Terminal Voltage (VV) to the Electromotive Force (EE). Since V=IRV = IR and E=I(R+r)E = I(R+r), the current II always cancels out, leaving you with just the resistances. Don't waste time trying to find the current!

    AI can make mistakes. Report anything that looks wrong.

  12. 12.

    The S.I unit of moment of a force is

    1. A.kgm
    2. B.Nm
    3. C.Jm
    4. D.µm−1^{-1}
    Show answer

    Answer: B. Nm

    AI explanation

    1. Analyze the question

    The question asks for the Standard International (S.I.) unit of the moment of a force.

    2. Explain the concept

    In physics, the moment of a force (also known as torque) is defined as the product of the force applied and the perpendicular distance from the pivot (or fulcrum) to the line of action of the force.

    The mathematical formula is:

    Moment=Force×Perpendicular Distance\text{Moment} = \text{Force} \times \text{Perpendicular Distance}
    • The S.I. unit of Force is the Newton (N).
    • The S.I. unit of Distance is the meter (m).

    Therefore, the unit of the moment of a force is the product of these two units.

    3. Show the solution
    • Step 1: Identify the formula: Moment=F×d\text{Moment} = F \times d
    • Step 2: Substitute the S.I. units: Unit=Newton×meter\text{Unit} = \text{Newton} \times \text{meter}
    • Step 3: Combine the units: Unit=Nm\text{Unit} = \text{Nm}

    While the Joule (J) is also a unit of energy (Force ×\times distance), the standard convention for expressing the moment of a force is Newton-meter (Nm) to distinguish it from energy.

    4. Identify the answer

    Comparing our result (Nm) with the given options: A. kgm B. Nm C. Jm D. µm−1^{-1}

    The correct option is B.

    5. Tip

    Don't confuse the Newton-meter (Nm) for a moment with the Joule (J) for work or energy. Even though they have the same dimensional formula (ML2T−2ML^2T^{-2}), we use Nm for moments to indicate that the force is applied perpendicularly to a distance, whereas Joules are used when force causes displacement in the direction of the force.

    AI can make mistakes. Report anything that looks wrong.

  13. 13.

    If silicon is doped with phosphorus, what type of semiconductor material will be formed?

    1. A.Zener material
    2. B.P-n junction
    3. C.n-type
    4. D.p-type
    Show answer

    Answer: C. n-type

    AI explanation

    Analysis

    The question asks about the effect of adding phosphorus (a Group 15 element) to silicon (a Group 14 element) in the context of semiconductor physics.

    Concept Explanation

    Semiconductors like Silicon (Si) have four valence electrons. To change their electrical properties, we perform a process called doping, which involves adding small amounts of impurities.

    • Intrinsic Semiconductors: Pure silicon.
    • n-type Semiconductors: Formed when silicon is doped with pentavalent elements (elements with 5 valence electrons), such as Phosphorus (P), Arsenic (As), or Antimony (Sb). Because the impurity has 5 electrons, 4 bond with the silicon atoms, leaving one "extra" electron free to move and conduct electricity. Since electrons are negatively charged, it is called an n-type (negative-type) semiconductor.
    • p-type Semiconductors: Formed when silicon is doped with trivalent elements (elements with 3 valence electrons), such as Boron (B) or Aluminum (Al). This creates a "hole" (a vacancy), which acts as a positive charge carrier.
    Step-by-Step Solution
    1. Identify the base material: Silicon is a Group 14 element with 4 valence electrons.
    2. Identify the dopant: Phosphorus is a Group 15 element with 5 valence electrons.
    3. Determine the effect: When Phosphorus is added to Silicon, the 5th electron of the Phosphorus atom does not participate in the covalent bonding with Silicon.
    4. Conclusion: This excess electron becomes a free charge carrier. Since the material now has an abundance of negative charge carriers (electrons), it is classified as an n-type semiconductor.
    Answer

    The correct option is C.

    Exam Tip

    Remember the mnemonic: Phosphorus = Pentavalent = n-type (think "n" for negative electrons). Conversely, Boron = Trivalent = p-type (think "p" for positive holes). This will help you quickly identify the type of semiconductor in any JAMB or WASSCE question!

    AI can make mistakes. Report anything that looks wrong.

  14. 14.

    Calculate the height of the image formed by a pinhole camera of length 12cm used to photograph an object 60cm away from the hole and 70cm high

    1. A.10 cm
    2. B.16 cm
    3. C.5 cm
    4. D.14 cm
    Show answer

    Answer: D. 14 cm

    Get a step-by-step AI explanation in the app

  15. 15.

    A block and tackle pulley arrangement has 6 pulleys in which an effort of 50N supports a load of 200N, calculate the efficiency of the machine

    1. A.80.0%
    2. B.76.6%
    3. C.66.7%
    4. D.60.7%
    Show answer

    Answer: C. 66.7%

    AI explanation

    1. Analyze the question

    We are given a block and tackle system with:

    • Number of pulleys (nn) = 6
    • Effort (EE) = 50 N
    • Load (LL) = 200 N
    • We need to find the Efficiency (η\eta) of the machine.
    2. Explain the concept

    Efficiency (η\eta) is the ratio of the Mechanical Advantage (MA) to the Velocity Ratio (VR), expressed as a percentage.

    • Mechanical Advantage (MA) = LoadEffort\frac{\text{Load}}{\text{Effort}}
    • Velocity Ratio (VR) = For a block and tackle system, the VR is equal to the total number of pulleys (nn) in the system.
    • Efficiency (η\eta) = MAVR×100%\frac{\text{MA}}{\text{VR}} \times 100\%
    3. Show the solution

    Step 1: Calculate the Mechanical Advantage (MA)

    MA=LoadEffort\text{MA} = \frac{\text{Load}}{\text{Effort}}
    MA=200 N50 N=4\text{MA} = \frac{200\text{ N}}{50\text{ N}} = 4

    Step 2: Identify the Velocity Ratio (VR) In a block and tackle system, the velocity ratio is equal to the number of pulleys.

    VR=6\text{VR} = 6

    Step 3: Calculate the Efficiency (η\eta)

    η=(MAVR)×100%\eta = \left( \frac{\text{MA}}{\text{VR}} \right) \times 100\%
    η=(46)×100%\eta = \left( \frac{4}{6} \right) \times 100\%
    η=(23)×100%\eta = \left( \frac{2}{3} \right) \times 100\%
    η=0.6667×100%\eta = 0.6667 \times 100\%
    η=66.67%\eta = 66.67\%
    4. Identify the answer

    Comparing our result to the given options, 66.7% matches option C.

    5. Exam Tip

    Always remember that for any machine, the Mechanical Advantage is always less than the Velocity Ratio due to friction. If you calculate an efficiency greater than 100%, you know you have swapped your MA and VR! Also, for block and tackle systems, the number of pulleys is your best friend for finding the VR quickly.

    AI can make mistakes. Report anything that looks wrong.

  16. 16.

    The instrument to measure the relative density of liquid is

    1. A.thermometer
    2. B.hydrometer
    3. C.spring balance
    4. D.beaker
    Show answer

    Answer: B. hydrometer

    AI explanation

    Analysis

    The question asks for the specific scientific instrument used to determine the relative density (or specific gravity) of a liquid.

    Concept Explanation

    Relative density is the ratio of the density of a substance to the density of a standard substance (usually water). To measure this efficiently in a laboratory setting, we use the principle of flotation (Archimedes' Principle). An object floats in a liquid when the weight of the liquid it displaces is equal to its own weight.

    • Hydrometer: This is a glass instrument designed to float in a liquid. It is calibrated with a scale that allows you to read the relative density directly based on how deep the instrument sinks into the liquid. The denser the liquid, the higher the hydrometer floats.
    Step-by-Step Evaluation
    • A. Thermometer: Used to measure temperature, not density.
    • B. Hydrometer: Specifically designed to measure the relative density of liquids. This is the correct tool.
    • C. Spring balance: Used to measure weight or force. While it can be used in an experiment to calculate density (by weighing an object in air and then in liquid), it is not an instrument designed for direct relative density measurement.
    • D. Beaker: A simple glass container used for holding or mixing liquids; it has no measurement scale for density.
    Conclusion

    The hydrometer is the standard instrument used for this purpose. It is commonly used in battery maintenance (to check electrolyte density) and in the dairy industry (to check the quality of milk).

    Exam Tip: Remember the "Hydro-" prefix usually relates to water or liquids. A Hydrometer measures liquid properties, while a Hygrometer (often confused with it) measures humidity in the air. Don't mix them up!

    AI can make mistakes. Report anything that looks wrong.

  17. 17.

    Determine the focal length of a thin converging lens if the power is 5.0 dioptres

    1. A.0.1 m
    2. B.0.2 m
    3. C.2.0 m
    4. D.2.5 m
    Show answer

    Answer: B. 0.2 m

    AI explanation

    Analysis

    The question asks for the focal length of a converging lens given its power in dioptres. This is a standard optics problem involving the relationship between the power of a lens and its focal length.

    Concept

    The power (PP) of a lens is defined as the reciprocal of its focal length (ff) when the focal length is measured in metres. The formula is:

    P=1fP = \frac{1}{f}

    Where:

    • PP is the power measured in dioptres (DD).
    • ff is the focal length measured in metres (mm).
    Solution
    1. Identify the given information: • Power (PP) = 5.0 D5.0\text{ D}
    1. Rearrange the formula to solve for ff: $f=1Pf = \frac{1}{P}$
    1. Substitute the values into the formula: $f=15.0f = \frac{1}{5.0}$
    1. Calculate the result: $f=0.2 mf = 0.2\text{ m}$

    The focal length of the lens is 0.2 metres0.2\text{ metres}.

    Conclusion

    Comparing our result to the given options: A. 0.1 m B. 0.2 m C. 2.0 m D. 2.5 m

    The correct option is B.

    Exam Tip

    Always remember that the unit for focal length must be in metres when using the power formula. If the question gives you the focal length in centimetres (e.g., 20 cm20\text{ cm}), you must convert it to metres (0.2 m0.2\text{ m}) before calculating the power, or use the formula P=100f(in cm)P = \frac{100}{f(\text{in cm})}. This simple check prevents common calculation errors in JAMB Physics!

    AI can make mistakes. Report anything that looks wrong.

  18. 18.

    Under what conditions are cathode rays produced in a discharge tube?

    1. A.High pressure and low voltage
    2. B.High pressure and high voltage
    3. C.Low pressure and low voltage
    4. D.Low pressure and high volatge
    Show answer

    Answer: D. Low pressure and high volatge

    AI explanation

    Analysis of the Question

    This question tests your understanding of the gas discharge phenomenon. To produce cathode rays (which are essentially a stream of electrons), you need to facilitate the ionization of gas molecules within a discharge tube.

    Concept Explanation

    A discharge tube contains a gas at a specific pressure with two electrodes (anode and cathode) connected to a high-voltage source.

    1. Why Low Pressure? At atmospheric pressure, air is a very good insulator. By reducing the pressure (using a vacuum pump), the distance between gas molecules increases. This allows electrons to gain enough kinetic energy to collide with gas molecules and cause ionization without being stopped by frequent collisions.
    2. Why High Voltage? A very high potential difference is required to provide the strong electric field necessary to accelerate the electrons and strip them from the cathode (or from the gas atoms) to sustain the flow of current.

    If the pressure is too high, the electrons collide too often and lose energy. If the voltage is too low, the electrons don't have enough energy to ionize the gas or be emitted from the cathode.

    Step-by-Step Solution
    • Step 1: Identify the requirements for gas discharge. We need to create a path for electrons to flow.
    • Step 2: Evaluate the pressure requirement. To allow electrons to travel freely without constant collisions with gas particles, the pressure must be significantly reduced (low pressure).
    • Step 3: Evaluate the voltage requirement. To overcome the resistance of the gas and pull electrons from the cathode, a very strong electric field is needed (high voltage).
    • Step 4: Combine these conditions. The production of cathode rays occurs specifically at low pressure and high voltage.
    Conclusion

    Comparing our findings with the given options, we see that Option D matches the physical requirements for the production of cathode rays.

    Exam Tip

    Think of a discharge tube like a crowded hallway (high pressure). If you want to run (electrons moving), you need the hallway to be empty (low pressure) and you need a strong push (high voltage) to get moving fast!

    AI can make mistakes. Report anything that looks wrong.

  19. 19.

    Three 3ω resistance are connected in parallel what is the equivalent resistance?

    1. A.1ω
    2. B.9ω
    3. C.3ω
    4. D.0.33ω
    Show answer

    Answer: A. 1ω

    AI explanation

    Analysis

    The question asks for the equivalent resistance of three resistors, each with a value of 3Ω3\Omega, connected in a parallel circuit.

    Concept

    When resistors are connected in parallel, the reciprocal of the equivalent resistance (ReqR_{eq}) is equal to the sum of the reciprocals of the individual resistances. The formula is:

    1Req=1R1+1R2+1R3\frac{1}{R_{eq}} = \frac{1}{R_1} + \frac{1}{R_2} + \frac{1}{R_3}

    Alternatively, for nn identical resistors of value RR connected in parallel, you can use the simplified formula:

    Req=RnR_{eq} = \frac{R}{n}
    Solution

    Given:

    • Resistance of each resistor (RR) = 3Ω3\Omega
    • Number of resistors (nn) = 33

    Using the standard formula:

    1Req=13+13+13\frac{1}{R_{eq}} = \frac{1}{3} + \frac{1}{3} + \frac{1}{3}
    1Req=1+1+13\frac{1}{R_{eq}} = \frac{1 + 1 + 1}{3}
    1Req=33\frac{1}{R_{eq}} = \frac{3}{3}
    1Req=1\frac{1}{R_{eq}} = 1
    Req=1ΩR_{eq} = 1\Omega

    Using the simplified formula:

    Req=RnR_{eq} = \frac{R}{n}
    Req=33R_{eq} = \frac{3}{3}
    Req=1ΩR_{eq} = 1\Omega

    The calculation confirms that the equivalent resistance is 1Ω1\Omega.

    Exam Tip

    In a parallel circuit, the equivalent resistance is always smaller than the smallest individual resistor in the circuit. If you ever calculate a value larger than your individual resistors, you know you have made a mistake! Also, remember the "shortcut": if all resistors are identical, just divide the value of one resistor by the total number of resistors.

    AI can make mistakes. Report anything that looks wrong.

  20. 20.

    Which of the following operations can be used to convert an alternative current dynamo into a direct current dynamo

    1. A.number of turns in the coil is increased
    2. B.strength of the field magnet is increased
    3. C.slip rings are replaced with split ring commutator
    4. D.coil is wound on a soft iron armature
    Show answer

    Answer: C. slip rings are replaced with split ring commutator

    AI explanation

    1. Analyze the question

    The question asks for the specific modification required to change an Alternating Current (AC) dynamo into a Direct Current (DC) dynamo.

    2. Explain the concept
    • AC Dynamo: Uses slip rings to connect the rotating coil to the external circuit. Because the coil rotates within a magnetic field, the direction of the induced current reverses every half-turn, resulting in an alternating current.
    • DC Dynamo: Requires the current to flow in only one direction in the external circuit. To achieve this, we use a split-ring commutator. The commutator acts as a mechanical rectifier; it reverses the connection to the external circuit at the exact moment the current in the coil reverses, ensuring the output current remains unidirectional (DC).
    3. Show the solution
    • Option A (Increasing turns): This increases the magnitude of the induced EMF (voltage), but it does not change the nature of the current from AC to DC.
    • Option B (Increasing field strength): This also increases the magnitude of the induced EMF, but it has no effect on the direction of the current.
    • Option C (Replacing slip rings with split ring commutator): As explained above, the split-ring commutator is the essential component that rectifies the alternating current produced in the armature into a direct current in the external circuit.
    • Option D (Soft iron armature): This is used to increase the magnetic flux linkage and improve efficiency, but it does not convert AC to DC.
    4. Identify the answer

    The correct operation is to replace the slip rings (which allow AC) with a split-ring commutator (which forces the current to flow in one direction).

    5. Tip

    Think of it this way: "Slip" rings allow the current to "slip" back and forth (AC), while a "Split" ring "splits" the connection to keep the current flowing in one direction (DC).

    AI can make mistakes. Report anything that looks wrong.

  21. 21.

    Which of the following is true of an electrical charge?

    1. A.Positive charge means deficit electrons
    2. B.Negative charge means excess of electrons
    3. C.electric current means movement of electrons
    4. D.All of the above
    Show answer

    Answer: D. All of the above

    AI explanation

    Analysis

    This question tests your fundamental understanding of electrostatics and current electricity. To solve this, we need to look at the definition of charge carriers and the nature of electric current.

    Concept Explanation
    1. Positive Charge: In an atom, protons are fixed in the nucleus, while electrons are mobile. When an object becomes positively charged, it is because it has lost electrons. Therefore, a positive charge represents a "deficit" or shortage of electrons.
    2. Negative Charge: Conversely, when an object gains extra electrons, it becomes negatively charged. Thus, a negative charge represents an "excess" of electrons.
    3. Electric Current: In metallic conductors (like the copper wires used in household wiring), electric current is defined as the flow or movement of free electrons through the conductor.
    Step-by-Step Solution
    • Option A: Since a positive charge is created by the removal of electrons, "deficit of electrons" is a correct description.
    • Option B: Since a negative charge is created by the addition of electrons, "excess of electrons" is a correct description.
    • Option C: In physics, we define current in a circuit as the rate of flow of charge, which, in solids, is specifically the movement of electrons. This is also correct.

    Since options A, B, and C are all scientifically accurate statements regarding electrical charges and current, option D must be the correct choice.

    Exam Tip

    When you see an "All of the above" option in a JAMB Physics question, always verify at least two of the options. If both are correct, you can confidently select "All of the above" without needing to spend extra time analyzing the third one. This saves you valuable time during the exam!

    AI can make mistakes. Report anything that looks wrong.

  22. 22.

    When two objects P and Q are supplied with the same quantity of heat, the temperature change in P is observed to be twice that of Q. The mass of P is half that of Q. The ratio of the specific heat capacity pf P to Q is

    1. A.1:4
    2. B.4:1
    3. C.1:1
    4. D.2:1
    Show answer

    Answer: C. 1:1

    Get a step-by-step AI explanation in the app

  23. 23.

    Which of the following instruments helps to maintain the correct humidity and temperature of a building?

    1. A.A compressor
    2. B.A refrigerator
    3. C.Air blower
    4. D.Air conditioner
    Show answer

    Answer: D. Air conditioner

    AI explanation

    Analysis

    The question asks for an instrument designed to regulate both the humidity (the amount of water vapor in the air) and the temperature (the degree of hotness or coldness) within an enclosed space like a building.

    Concept Explanation

    To understand this, we look at the functions of the options provided:

    • Compressor: This is a component inside cooling systems that increases the pressure of a refrigerant. It is not a complete system on its own.
    • Refrigerator: This is designed to keep a small, insulated compartment cold to preserve food. It does not regulate the humidity and temperature of an entire building.
    • Air blower: This simply moves air from one place to another; it does not change the temperature or humidity of the air.
    • Air conditioner: This is a system designed to provide thermal comfort and indoor air quality. It works by drawing in warm air, passing it over cooling coils (which removes heat and condenses excess moisture/humidity), and circulating the cooled, dehumidified air back into the room.
    Step-by-Step Solution
    1. Temperature Control: An air conditioner uses a refrigeration cycle to remove heat from the indoor air, effectively lowering the temperature.
    2. Humidity Control: As the warm, moist indoor air passes over the cold evaporator coils of the air conditioner, the water vapor in the air condenses into liquid water (which is then drained away). This process significantly reduces the humidity level in the room.
    3. Conclusion: Because the air conditioner performs both the cooling of the air and the removal of excess moisture, it is the correct device for maintaining a controlled environment in a building.
    Identifying the Answer

    Comparing the functions, the Air conditioner is the only device listed that is specifically engineered to manage both environmental factors (temperature and humidity) for human comfort in a building.

    Exam Tip

    When you see questions about "environmental control" in Physics, look for devices that involve a thermodynamic cycle. An air conditioner is essentially a heat pump that moves heat from inside a building to the outside, and the cooling process naturally acts as a dehumidifier.

    AI can make mistakes. Report anything that looks wrong.

  24. 24.

    The volume of a fixed mass of gas is 10cm3 when its pressure is 400cmHg. Determine the volume of the gas when its pressure is 200cmHg.

    1. A.30cm3
    2. B.40cm3
    3. C.50cm3
    4. D.20cm3
    Show answer

    Answer: D. 20cm3

    AI explanation

    1. Analyze the question

    We are given the initial volume (V1V_1) and initial pressure (P1P_1) of a fixed mass of gas. We need to find the new volume (V2V_2) when the pressure changes to a new value (P2P_2), assuming the temperature remains constant.

    2. Explain the concept

    This problem is governed by Boyle’s Law. Boyle’s Law states that for a fixed mass of gas at a constant temperature, the pressure (PP) is inversely proportional to the volume (VV).

    The formula is:

    P1V1=P2V2P_1V_1 = P_2V_2

    Where:

    • P1P_1 = Initial pressure
    • V1V_1 = Initial volume
    • P2P_2 = Final pressure
    • V2V_2 = Final volume
    3. Show the solution

    Given data:

    • V1=10 cm3V_1 = 10\text{ cm}^3
    • P1=400 cmHgP_1 = 400\text{ cmHg}
    • P2=200 cmHgP_2 = 200\text{ cmHg}
    • V2=?V_2 = ?

    Step-by-step calculation: Using the formula P1V1=P2V2P_1V_1 = P_2V_2:

    (400 cmHg)×(10 cm3)=(200 cmHg)×V2(400\text{ cmHg}) \times (10\text{ cm}^3) = (200\text{ cmHg}) \times V_2
    4000=200×V24000 = 200 \times V_2

    To find V2V_2, divide both sides by 200:

    V2=4000200V_2 = \frac{4000}{200}
    V2=20 cm3V_2 = 20\text{ cm}^3
    4. Identify the answer

    Comparing our result to the given options, the correct answer is D.

    5. Tip

    When using Boyle's Law, remember the relationship: If pressure is halved, volume must double. In this question, the pressure dropped from 400 to 200 (it was halved), so the volume must increase from 10 to 20 (it doubled). This is a quick way to verify your answer without even needing a calculator!

    AI can make mistakes. Report anything that looks wrong.

  25. 25.

    The instrument used to measure the pressure of a gas is

    1. A.barometer
    2. B.thermometer
    3. C.hydrometer
    4. D.manometer
    Show answer

    Answer: D. manometer

    AI explanation

    Analysis

    The question asks for the specific scientific instrument designed to measure the pressure of a gas, particularly in a laboratory or enclosed system setting.

    Concept Explanation

    To identify the correct instrument, we must understand the function of each device listed:

    • Barometer: Used primarily to measure atmospheric pressure. It is commonly used in weather forecasting.
    • Thermometer: Used to measure temperature (the degree of hotness or coldness of a body).
    • Hydrometer: Used to measure the relative density (specific gravity) of liquids. It is often used to check the state of charge of a lead-acid battery.
    • Manometer: A device consisting of a U-shaped tube containing a liquid (usually mercury or water). It is specifically designed to measure the pressure of a gas or vapor by comparing the difference in liquid levels between the two arms of the tube.
    Step-by-Step Solution
    1. Evaluate the options: We eliminate the thermometer (measures temperature) and the hydrometer (measures density).
    2. Distinguish between Barometer and Manometer: While both measure pressure, a barometer is fixed to measure the ambient atmospheric pressure. A manometer is the versatile tool used to measure the pressure of a gas trapped in a container or flowing through a pipe.
    3. Conclusion: Since the question asks for the instrument used to measure the pressure of a gas (often in a closed system), the manometer is the correct scientific instrument.
    Exam Tip

    Think of the "M" in Manometer as standing for "Measurement of gas pressure." Don't confuse it with the Barometer, which is strictly for the "B"ig atmosphere!

    AI can make mistakes. Report anything that looks wrong.

  26. 26.

    An element and its isotope only differ in the number of

    1. A.protons
    2. B.electrons
    3. C.ions
    4. D.neutrons
    Show answer

    Answer: D. neutrons

    AI explanation

    1. Analyze the question

    The question asks for the fundamental subatomic difference between an element and its isotope. To answer this, we must recall the definitions of atomic structure and isotopes.

    2. Explain the concept
    • Atomic Number (ZZ): This represents the number of protons in the nucleus of an atom. The atomic number defines the identity of an element (e.g., all Carbon atoms have 6 protons).
    • Mass Number (AA): This is the sum of the protons and neutrons in the nucleus (A=Z+NA = Z + N).
    • Isotopes: These are atoms of the same element that have the same number of protons (same atomic number) but a different number of neutrons. Because they have different numbers of neutrons, they also have different mass numbers.
    3. Show the solution
    • If an atom changes its number of protons, it becomes a completely different element (e.g., changing from Carbon to Nitrogen).
    • If an atom changes its number of electrons, it becomes an ion (charged particle), not a different isotope.
    • If an atom changes its number of neutrons, the chemical identity (protons) remains the same, but the mass of the atom changes. This is the definition of an isotope.

    Therefore, isotopes are atoms of the same element that differ only in their neutron count.

    4. Identify the answer

    Comparing our explanation to the given options:

    • A is incorrect because protons define the element.
    • B is incorrect because electrons determine the charge/chemical bonding.
    • C is incorrect because ions are charged atoms.
    • D is correct because the variation in neutrons is what creates isotopes.
    5. Tip

    Memory Trick: Think of the word "Isotope" as having an "n" for "neutrons".

    • Isotope = Same protons, different neutrons.

    AI can make mistakes. Report anything that looks wrong.

  27. 27.

    How can energy loss be minimized through Eddy-current?

    1. A.By using high resistance wire
    2. B.By using insulated soft iron wires
    3. C.By using low resistance wires
    4. D.Bu using turns of wires
    Show answer

    Answer: B. By using insulated soft iron wires

    AI explanation

    Analysis

    The question asks for the method used to minimize energy loss caused by Eddy currents in electrical machines like transformers and motors.

    Concept Explanation

    Eddy currents are circular loops of induced current that flow within the core of a transformer or motor when it is subjected to a changing magnetic field. According to Lenz's Law, these currents create their own magnetic fields that oppose the change, leading to:

    1. Energy loss: Energy is dissipated as heat (I2RI^2R loss).
    2. Overheating: This can damage the insulation of the device.

    To minimize these losses, engineers use a technique called lamination. Instead of using a solid block of metal for the core, they use thin sheets (laminations) of soft iron. Each sheet is coated with an insulating material (like varnish). This insulation breaks the path of the eddy currents, forcing them to stay within a very small area, which significantly reduces their magnitude and the resulting heat loss.

    Step-by-Step Solution
    1. Identify the cause: Eddy currents flow in solid metal cores because the metal provides a low-resistance path for the induced currents to circulate.
    2. Evaluate the options: • A (High resistance wire): This relates to reducing current in a circuit, not the eddy currents within a core. • B (Insulated soft iron wires/sheets): By using thin, insulated sheets (laminations), the path for eddy currents is restricted, effectively minimizing energy loss. This is the standard engineering practice. • C (Low resistance wires): Low resistance would actually increase the flow of eddy currents, leading to more energy loss. • D (Turns of wires): This relates to the number of turns in a coil (transformer ratio), not the core material properties.
    3. Conclusion: The use of insulated soft iron laminations is the correct physical principle to minimize eddy current losses.
    Correct Answer

    The correct option is B.

    Exam Tip

    Whenever you see a question about "Eddy currents" in JAMB or WASSCE, look for keywords like "Lamination" or "Insulated sheets." Remember: Lamination = Less Eddy Current = Less Heat Loss.

    AI can make mistakes. Report anything that looks wrong.

  28. 28.

    When two mirrors are placed at an angle of 90º to each other, how many images will be formed when an object is placed in front of the mirrors

    1. A.5
    2. B.4
    3. C.3
    4. D.2
    Show answer

    Answer: C. 3

    AI explanation

    Analysis

    The question asks for the number of images formed when an object is placed between two plane mirrors inclined at a specific angle (θ=90∘\theta = 90^\circ).

    Concept

    When two plane mirrors are inclined at an angle θ\theta, the number of images (nn) formed is determined by the formula:

    n=(360∘θ)−1n = \left( \frac{360^\circ}{\theta} \right) - 1

    This formula is used when the result of 360∘θ\frac{360^\circ}{\theta} is an even integer. If the result is an odd integer, the formula remains the same if the object is placed asymmetrically, but if the object is placed symmetrically, the number of images is 360∘θ−1\frac{360^\circ}{\theta} - 1. However, for a 90∘90^\circ angle, the calculation is straightforward.

    Solution
    1. Identify the given angle: θ=90∘\theta = 90^\circ
    2. Calculate the ratio: $360∘90∘=4\frac{360^\circ}{90^\circ} = 4$
    3. Apply the formula: Since 4 is an even number, we subtract 1 to account for the overlapping images: $n=4−1=3n = 4 - 1 = 3$

    Therefore, 3 images will be formed.

    Conclusion

    The correct option is C.

    Exam Tip

    A quick way to remember this is the "Even-Odd Rule":

    • If 360θ\frac{360}{\theta} is even, the number of images is 360θ−1\frac{360}{\theta} - 1.
    • If 360θ\frac{360}{\theta} is odd, the number of images is 360θ−1\frac{360}{\theta} - 1 (for symmetric placement) or simply 360θ\frac{360}{\theta} (for asymmetric placement).
    • If 360θ\frac{360}{\theta} is a fraction, the number of images is the integer part of the result.

    AI can make mistakes. Report anything that looks wrong.

  29. 29.

    Which of the following surfaces will absorb radiant heat energy?

    1. A.white
    2. B.red
    3. C.black
    4. D.blue
    Show answer

    Answer: C. black

    Get a step-by-step AI explanation in the app

  30. 30.

    A man of mass 50kg ascends a flight of stains 5m high in 5 seconds. If acceleration due to gravity is 10ms−2^{-2} the power expended is

    1. A.100w
    2. B.200w
    3. C.400w
    4. D.500w
    Show answer

    Answer: D. 500w

    AI explanation

    Analysis

    To solve this problem, we need to calculate the power expended by the man. Power is defined as the rate at which work is done or the rate at which energy is transferred.

    Concept

    The formula for Power (PP) is:

    P=Work DoneTime takenP = \frac{\text{Work Done}}{\text{Time taken}}

    Since the man is ascending a height, the work done is equal to the gravitational potential energy gained, which is given by:

    Work Done=Force×Distance=mgh\text{Work Done} = \text{Force} \times \text{Distance} = mgh

    Where:

    • mm = mass of the man (kg)
    • gg = acceleration due to gravity (ms−2^{-2})
    • hh = height (m)

    Combining these, the formula for power becomes:

    P=mghtP = \frac{mgh}{t}
    Step-by-Step Solution
    1. Identify the given values: • Mass (mm) = 50 kg • Height (hh) = 5 m • Time (tt) = 5 s • Acceleration due to gravity (gg) = 10 ms−2^{-2}
    1. Calculate the Work Done: $Work=m×g×h\text{Work} = m \times g \times h$ $Work=50×10×5\text{Work} = 50 \times 10 \times 5$ $Work=2500 Joules\text{Work} = 2500 \text{ Joules}$
    1. Calculate the Power: $P=WorktP = \frac{\text{Work}}{t}$ $P=25005P = \frac{2500}{5}$ $P=500 WattsP = 500 \text{ Watts}$
    Conclusion

    Comparing our result to the given options, the power expended is 500W.

    Exam Tip: Always check your units before calculating. If the mass were in grams, you would need to convert it to kilograms first. Also, remember that 1 Watt=1 Joule/second1 \text{ Watt} = 1 \text{ Joule/second}. Keeping your units consistent is the best way to avoid silly mistakes in JAMB Physics!

    AI can make mistakes. Report anything that looks wrong.

  31. 31.

    Calculate the angle of minimum deviation of a 60º prism of a refractive index 1.5[ sin−1sin^{-1} (0.75) = 49º]

    1. A.38o
    2. B.19.47o
    3. C.16.25o
    4. D.49o
    Show answer

    Answer: A. 38o

    AI explanation

    1. Analyze the question

    We are given:

    • The refracting angle of the prism (AA) = 60∘60^\circ
    • The refractive index of the prism (nn) = 1.51.5
    • We need to find the angle of minimum deviation (DmD_m).
    2. Explain the concept

    For a prism, the relationship between the refractive index (nn), the refracting angle (AA), and the angle of minimum deviation (DmD_m) is given by the formula:

    n=sin⁡(A+Dm2)sin⁡(A2)n = \frac{\sin\left(\frac{A + D_m}{2}\right)}{\sin\left(\frac{A}{2}\right)}
    3. Show the solution

    Step 1: Substitute the known values into the formula.

    1.5=sin⁡(60∘+Dm2)sin⁡(60∘2)1.5 = \frac{\sin\left(\frac{60^\circ + D_m}{2}\right)}{\sin\left(\frac{60^\circ}{2}\right)}

    Step 2: Simplify the denominator.

    sin⁡(60∘2)=sin⁡(30∘)=0.5\sin\left(\frac{60^\circ}{2}\right) = \sin(30^\circ) = 0.5

    Step 3: Solve for the sine term.

    1.5=sin⁡(60∘+Dm2)0.51.5 = \frac{\sin\left(\frac{60^\circ + D_m}{2}\right)}{0.5}
    1.5×0.5=sin⁡(60∘+Dm2)1.5 \times 0.5 = \sin\left(\frac{60^\circ + D_m}{2}\right)
    0.75=sin⁡(60∘+Dm2)0.75 = \sin\left(\frac{60^\circ + D_m}{2}\right)

    Step 4: Use the inverse sine to find the angle. The question provides the hint: sin⁡−1(0.75)=49∘\sin^{-1}(0.75) = 49^\circ.

    60∘+Dm2=49∘\frac{60^\circ + D_m}{2} = 49^\circ

    Step 5: Solve for DmD_m.

    60∘+Dm=49∘×260^\circ + D_m = 49^\circ \times 2
    60∘+Dm=98∘60^\circ + D_m = 98^\circ
    Dm=98∘−60∘D_m = 98^\circ - 60^\circ
    Dm=38∘D_m = 38^\circ
    4. Identify the answer

    Comparing our result (38∘38^\circ) to the given options, it matches option A.

    5. Tip

    When dealing with prism problems, always remember that at minimum deviation, the light ray passes symmetrically through the prism. This symmetry is why the angle of incidence equals the angle of emergence, which simplifies the math significantly!

    AI can make mistakes. Report anything that looks wrong.

  32. 32.

    What is the cost of running seven 40 W lamps and five 80 W lamps for 12 hours of the electrical energy cost N7.00kWh?

    1. A.N80.00
    2. B.N45.36
    3. C.N65.00
    4. D.N57.12
    Show answer

    Answer: D. N57.12

    Get a step-by-step AI explanation in the app

  33. 33.

    Which of the following is not true of an electrical charge?

    1. A.Negative charge means deficit electrons
    2. B.Negative charge means excess of electrons
    3. C.electric current means movement of electrons
    4. D.All of the above
    Show answer

    Answer: A. Negative charge means deficit electrons

    AI explanation

    Analysis

    The question asks us to identify the statement that is not true regarding electrical charges and current. We need to evaluate each option based on the fundamental principles of electrostatics and current electricity.

    Concept Explanation
    1. Nature of Charge: Atoms consist of protons (positive) in the nucleus and electrons (negative) orbiting the nucleus. An object becomes negatively charged when it gains extra electrons (an excess) and positively charged when it loses electrons (a deficit).
    2. Electric Current: In metallic conductors, electric current is defined as the flow or movement of free electrons through the material.
    Step-by-Step Solution
    • Option A: "Negative charge means deficit electrons" • If an object has a deficit of electrons, it means there are more protons than electrons. This results in a positive charge, not a negative one. Therefore, this statement is false.
    • Option B: "Negative charge means excess of electrons" • If an object has an excess of electrons, it has more negative particles than positive ones. This results in a negative charge. This statement is true.
    • Option C: "Electric current means movement of electrons" • In conductors, the flow of charge is indeed the flow of electrons. This statement is true.

    Since the question asks for the statement that is not true, and Option A describes a positive charge rather than a negative one, Option A is the correct choice.

    Conclusion

    The statement "Negative charge means deficit electrons" is scientifically incorrect because a deficit of electrons results in a positive charge.

    Exam Tip: Always remember the mnemonic "P-E-D": Positive = Electron Deficit. This will help you avoid confusion between positive and negative charging processes in your exams.

    AI can make mistakes. Report anything that looks wrong.

  34. 34.

    A string of length 5cm is extended by 0.04m when a load of 0.8kg is suspended at the end. How far will it extend if a force of 16N is applied? [g = 10ms−2^{-2}]

    1. A.0.04m
    2. B.0.12m
    3. C.0.01m
    4. D.0.08m
    Show answer

    Answer: D. 0.08m

    AI explanation

    Analysis

    To solve this problem, we use Hooke’s Law, which states that the extension of an elastic material is directly proportional to the force applied, provided the elastic limit is not exceeded. The formula is:

    F=keF = ke

    Where:

    • FF = Force (in Newtons)
    • kk = Force constant (stiffness of the string)
    • ee = Extension (in meters)
    Step-by-Step Solution

    Step 1: Calculate the force applied in the first scenario. The load is given as 0.8 kg0.8\text{ kg}. To find the force (F1F_1), we use F=mgF = mg:

    F1=0.8 kg×10 ms−2=8 NF_1 = 0.8\text{ kg} \times 10\text{ ms}^{-2} = 8\text{ N}

    Step 2: Find the force constant (kk) of the string. Using the first scenario where F1=8 NF_1 = 8\text{ N} and extension e1=0.04 me_1 = 0.04\text{ m}:

    k=F1e1=8 N0.04 mk = \frac{F_1}{e_1} = \frac{8\text{ N}}{0.04\text{ m}}
    k=200 N/mk = 200\text{ N/m}

    Step 3: Calculate the extension for the second force. Now, we apply a force F2=16 NF_2 = 16\text{ N} to the same string (the constant kk remains the same):

    e2=F2ke_2 = \frac{F_2}{k}
    e2=16 N200 N/me_2 = \frac{16\text{ N}}{200\text{ N/m}}
    e2=0.08 me_2 = 0.08\text{ m}
    Conclusion

    The string will extend by 0.08 m0.08\text{ m} when a force of 16 N16\text{ N} is applied.

    Exam Tip: In questions involving Hooke's Law, you can also use the ratio method to save time:

    F1e1=F2e2\frac{F_1}{e_1} = \frac{F_2}{e_2}

    Since F2F_2 (16 N16\text{ N}) is exactly double F1F_1 (8 N8\text{ N}), the extension e2e_2 must also be double the original extension e1e_1 (0.04 m×2=0.08 m0.04\text{ m} \times 2 = 0.08\text{ m}). This shortcut is very useful for JAMB where time management is key!

    AI can make mistakes. Report anything that looks wrong.

  35. 35.

    A radio station broadcast at a frequency of 600KHZ. If the speed of light in air is 3 × 108ms−1^{−1}. Calculate the wavelength of the radio wave

    1. A.2.20 × 103^3m
    2. B.5.0 × 102^2m
    3. C.5.0 × 105^5m
    4. D.11.8 × 1011^{11}m
    Show answer

    Answer: B. 5.0 × 102^2m

    AI explanation

    Analysis

    To solve this problem, we need to relate the speed of a wave, its frequency, and its wavelength. This is a classic wave equation problem frequently tested in JAMB Physics.

    Concept

    The relationship between the speed of a wave (vv), its frequency (ff), and its wavelength (λ\lambda) is given by the formula:

    v=f×λv = f \times \lambda

    Where:

    • vv = speed of light (3×108 m/s3 \times 10^8 \text{ m/s})
    • ff = frequency (in Hertz)
    • λ\lambda = wavelength (in meters)

    To find the wavelength, we rearrange the formula:

    λ=vf\lambda = \frac{v}{f}
    Step-by-Step Solution

    Step 1: Convert units to SI units. The frequency is given in kilohertz (kHz). We must convert this to Hertz (Hz):

    • f=600 kHz=600×103 Hzf = 600 \text{ kHz} = 600 \times 10^3 \text{ Hz}
    • f=6×105 Hzf = 6 \times 10^5 \text{ Hz}

    Step 2: Apply the formula. Substitute the values into the rearranged equation:

    λ=3×108 m/s6×105 Hz\lambda = \frac{3 \times 10^8 \text{ m/s}}{6 \times 10^5 \text{ Hz}}

    Step 3: Perform the calculation.

    • Divide the coefficients: 3÷6=0.53 \div 6 = 0.5
    • Divide the powers of 10: 108÷105=10(8−5)=10310^8 \div 10^5 = 10^{(8-5)} = 10^3
    • Combine them: λ=0.5×103 m\lambda = 0.5 \times 10^3 \text{ m}

    Step 4: Convert to standard scientific notation.

    • 0.5×103=5×10−1×103=5×102 m0.5 \times 10^3 = 5 \times 10^{-1} \times 10^3 = 5 \times 10^2 \text{ m}
    Conclusion

    Comparing our result to the given options, we find that 5.0×102 m5.0 \times 10^2 \text{ m} matches option B.

    Exam Tip

    Always watch out for prefixes like k (kilo = 10310^3), M (mega = 10610^6), or n (nano = 10−910^{-9}). JAMB examiners love to test your ability to convert these prefixes to standard SI units before plugging them into your formulas. If you forget to convert kHz to Hz, your answer will be off by a factor of 1,000!

    AI can make mistakes. Report anything that looks wrong.

  36. 36.This question needs a diagram, table or passage that we don't have yet, so it isn't shown.

  37. 37.

    Calculate the upthrust on an object of volume 50cm3 which is immersed in liquid of density 10310^{3} kgm-3 [g = 10ms−2ms^{-2}]

    1. A.0.8N
    2. B.2.5N
    3. C.0.5N
    4. D.1.0N
    Show answer

    Answer: C. 0.5N

    Get a step-by-step AI explanation in the app

  38. 38.

    The action of blotting paper on ink is due to

    1. A.diffusion
    2. B.osmosis
    3. C.capillarity
    4. D.surface tension
    Show answer

    Answer: C. capillarity

    Get a step-by-step AI explanation in the app

  39. 39.

    I. Refraction II. Interference III. Diffraction Which of the above properties are common to all waves?

    1. A.II and III only
    2. B.I, II and III
    3. C.I and II only
    4. D.I and III only
    Show answer

    Answer: B. I, II and III

    Get a step-by-step AI explanation in the app

  40. 40.

    Calculate the time taken for a mango fruit that fall from the tree 20 m to the ground [g = 10 ms−2ms^{-2}]

    1. A.10s
    2. B.5s
    3. C.4s
    4. D.2s
    Show answer

    Answer: D. 2s

    Get a step-by-step AI explanation in the app

  41. 41.

    Which of the following is a scalar quantity?

    1. A.Tension
    2. B.Weight
    3. C.Impulse
    4. D.Mass
    Show answer

    Answer: D. Mass

    Get a step-by-step AI explanation in the app

  42. 42.This question needs a diagram, table or passage that we don't have yet, so it isn't shown.

  43. 43.

    Why do soldiers march disorderly while crossing a bridge?

    1. A.To prevent resonance on the bridge
    2. B.To set the bridge into resonance
    3. C.To make the b ridge collapse
    4. D.To spread their weight evenly on the bridge
    Show answer

    Answer: A. To prevent resonance on the bridge

    AI explanation

    Analysis of the Question

    This question tests your understanding of Resonance in Physics. It asks why a specific behavior (marching disorderly) is required when soldiers cross a bridge.

    Concept Explanation: Resonance

    Resonance occurs when an external force or a vibrating system forces another system to oscillate with greater amplitude at a specific frequency, known as its natural frequency.

    Every physical structure, including a bridge, has a natural frequency at which it vibrates. If a rhythmic force (like soldiers marching in perfect unison) matches the natural frequency of the bridge, the bridge will begin to vibrate with increasing amplitude. If these vibrations become too large, the structural integrity of the bridge can be compromised, potentially leading to a collapse.

    Step-by-Step Solution
    1. The Problem: When soldiers march in step, they create a periodic, rhythmic force on the bridge. If the frequency of their steps matches the natural frequency of the bridge, the bridge enters a state of resonance.
    2. The Effect: During resonance, the bridge undergoes large oscillations (vibrations). These vibrations exert immense stress on the materials of the bridge.
    3. The Solution: By marching "disorderly" (breaking the rhythm or step), the soldiers ensure that their footsteps do not have a single, consistent frequency. This prevents the buildup of resonant vibrations, keeping the bridge stable and safe.
    4. Evaluating the Options: • A: This is correct. Breaking the rhythm prevents the frequency of the footsteps from matching the natural frequency of the bridge. • B: This is incorrect. Setting the bridge into resonance is exactly what they want to avoid. • C: This is incorrect. Soldiers aim to cross the bridge safely, not destroy it. • D: This is incorrect. Marching disorderly does not change the total weight or the distribution of weight; it only changes the frequency of the force applied.
    Conclusion

    Exam Tip: Whenever you see a question about soldiers on a bridge or a car vibrating at a certain speed, think Resonance. The goal is always to avoid matching the "natural frequency" of the object.

    AI can make mistakes. Report anything that looks wrong.

  44. 44.

    What is the speed of a body vibrating at 50 cyclic per second

    1. A.100 πrads−1_{−1}
    2. B.200 πrads−1_{−1}
    3. C.50 πrads−1_{−1}
    4. D.400 πrads−1_{−1}
    Show answer

    Answer: A. 100 πrads−1_{−1}

    AI explanation

    Analysis

    The question asks for the "speed" of a vibrating body given its frequency. In the context of simple harmonic motion (SHM) and waves, the term "speed" here refers to the angular velocity (or angular frequency), which is measured in radians per second (rad s−1\text{rad s}^{-1}).

    Concept

    For a body vibrating with a frequency (ff), the angular velocity (ω\omega) is given by the formula:

    ω=2πf\omega = 2\pi f

    Where:

    • ω\omega = angular velocity (in rad s−1\text{rad s}^{-1})
    • ff = frequency (in cycles per second or Hertz)
    • π\pi = a constant (approximately 3.142)
    Solution
    1. Identify the given value: The frequency (ff) is given as 50 cycles per second (or 50 Hz).
    1. Apply the formula: $ω=2×π×f\omega = 2 \times \pi \times f$ $ω=2×π×50\omega = 2 \times \pi \times 50$
    1. Calculate the result: $ω=100π rad s−1\omega = 100\pi \text{ rad s}^{-1}$
    Conclusion

    Comparing our result to the provided options, the correct value is 100π rad s−1100\pi \text{ rad s}^{-1}. This matches option A.

    Exam Tip

    Always pay attention to the units in the options. If the question asks for "speed" in a vibration context and the options have rad s−1\text{rad s}^{-1}, it is a clear signal that you are being asked to calculate the angular frequency (ω\omega), not the linear velocity (v=ωrv = \omega r). Don't let the terminology confuse you!

    AI can make mistakes. Report anything that looks wrong.

  45. 45.

    Which of the following is not a mechanical wave?

    1. A.wave in closed pipe
    2. B.radio waves
    3. C.water waves
    4. D.sound waves
    Show answer

    Answer: B. radio waves

    AI explanation

    1. Analyze the question

    The question asks us to identify which of the listed options is not a mechanical wave. To answer this, we must distinguish between mechanical waves and electromagnetic waves.

    2. Explain the concept
    • Mechanical Waves: These are waves that require a material medium (solid, liquid, or gas) to propagate. They involve the oscillation of particles in the medium. Examples include sound waves, water waves, and waves in strings or pipes.
    • Electromagnetic (EM) Waves: These are waves that do not require a material medium to propagate. They can travel through a vacuum (empty space). They consist of oscillating electric and magnetic fields. Examples include radio waves, light, X-rays, and gamma rays.
    3. Show the solution
    • Option A (Wave in a closed pipe): This is a sound wave trapped in a medium (air). It is a mechanical wave.
    • Option B (Radio waves): These are part of the electromagnetic spectrum. They travel at the speed of light and do not need a medium to travel; they can pass through the vacuum of space. Therefore, they are not mechanical waves.
    • Option C (Water waves): These require water (a medium) to travel. They are mechanical waves.
    • Option D (Sound waves): These require air, water, or solids to travel. They are mechanical waves.
    4. Identify the answer

    Comparing the options, radio waves are the only ones that are electromagnetic, not mechanical.

    5. Tip

    To remember the difference, use the acronym "RMIVUXG" for the electromagnetic spectrum (Radio, Microwave, Infrared, Visible light, Ultraviolet, X-ray, Gamma). None of these require a medium to travel, so if you see any of these in an exam question asking for "non-mechanical" waves, you know exactly what to pick!

    AI can make mistakes. Report anything that looks wrong.

  46. 46.

    Which of the following statements is NOT correct?

    1. A.Molecules of a liquid are stationary
    2. B.Brownian motion is an evidence of particle nature of matter
    3. C.Matter is made up of molecules
    4. D.The molecules of matter are in constant motion
    Show answer

    Answer: A. Molecules of a liquid are stationary

    AI explanation

    Analysis

    The question asks us to identify the incorrect statement among the four options provided regarding the kinetic theory of matter.

    Concept Explanation

    The Kinetic Theory of Matter is a fundamental principle in Physics that describes the behavior of matter. Its core tenets include:

    1. Particle Nature: All matter is composed of tiny, discrete particles (atoms or molecules).
    2. Constant Motion: These particles are in a state of continuous, random motion. Even in solids, particles vibrate about fixed positions; in liquids and gases, they move more freely.
    3. Brownian Motion: This is the random, zig-zag movement of particles suspended in a fluid (liquid or gas), caused by collisions with the fast-moving molecules of the fluid. It serves as direct evidence that matter is made of particles in constant motion.
    Step-by-Step Evaluation
    • Option A: "Molecules of a liquid are stationary." According to the kinetic theory, molecules in a liquid are not stationary; they possess kinetic energy and move past one another, which is why liquids can flow. Therefore, this statement is incorrect.
    • Option B: "Brownian motion is an evidence of particle nature of matter." This is a correct statement, as Brownian motion proves that invisible particles are constantly colliding with visible ones.
    • Option C: "Matter is made up of molecules." This is a correct statement, as it defines the basic composition of matter.
    • Option D: "The molecules of matter are in constant motion." This is a correct statement, as it aligns with the fundamental kinetic theory of matter.
    Conclusion

    Since the question asks for the statement that is NOT correct, Option A is the right choice because molecules in a liquid are definitely in motion, not stationary.

    Exam Tip

    When you see "NOT" or "EXCEPT" in a JAMB question, circle it immediately! It is easy to accidentally pick the first correct statement you see. Always double-check that you are selecting the false statement, not the true ones.

    AI can make mistakes. Report anything that looks wrong.

  47. 47.

    The velocity ratio of an inclined plane where angle of inclination in θ is

    1. A.Sinθ
    2. B.Cosθ
    3. C.Tanθ
    4. D.1sin⁡θ\frac{1}{\sin \theta}
    Show answer

    Answer: D. 1sin⁡θ\frac{1}{\sin \theta}

    Get a step-by-step AI explanation in the app

  48. 48.

    Which of the following is a semiconductor

    1. A.copper
    2. B.silicon
    3. C.plastic
    4. D.Iron
    Show answer

    Answer: B. silicon

    AI explanation

    Analysis

    The question asks us to identify which of the given materials is classified as a semiconductor. To answer this, we need to understand the electrical classification of materials based on their conductivity.

    Concept Explanation

    Materials are generally classified into three categories based on their ability to conduct electricity:

    1. Conductors: These are materials that allow electric current to flow through them easily. They have a high number of free electrons. Examples include metals like copper, iron, aluminum, and gold.
    2. Insulators: These are materials that do not allow electric current to flow through them. Their electrons are tightly bound to their atoms. Examples include plastic, rubber, glass, and wood.
    3. Semiconductors: These are materials that have electrical conductivity between that of a conductor and an insulator. Their conductivity can be modified by adding impurities (doping) or by changing the temperature. The most common elements used as semiconductors in electronics are Silicon (Si) and Germanium (Ge).
    Step-by-Step Solution
    • Option A (Copper): Copper is a metal and a very good conductor of electricity. It is used in electrical wiring.
    • Option B (Silicon): Silicon is a metalloid. Its atomic structure allows it to act as an insulator at low temperatures and a conductor at higher temperatures or when doped. It is the fundamental material used to manufacture transistors, diodes, and computer chips.
    • Option C (Plastic): Plastic is a non-metal and a poor conductor of electricity. It is widely used as an insulator to cover electrical wires.
    • Option D (Iron): Iron is a transition metal and a conductor of electricity.

    Comparing these to our definition, Silicon is the only material listed that functions as a semiconductor.

    Exam Tip

    When you see questions about semiconductors in JAMB or WASSCE, always look for Silicon or Germanium. If you see metals like Copper, Iron, or Aluminum, they are conductors; if you see non-metals like Plastic, Wood, or Rubber, they are insulators.

    AI can make mistakes. Report anything that looks wrong.

  49. 49.

    Under which of the following conditions is workdone

    1. A.A man supports a heavy food above his head with his hands
    2. B.A boy climbs onto a table
    3. C.A man pushes unto a table
    4. D.A woman holds a pot of water
    Show answer

    Answer: B. A boy climbs onto a table

    AI explanation

    Analysis of the Question

    In Physics, work is defined as the product of the force applied to an object and the displacement (distance moved) in the direction of that force. The formula is:

    W=F×d×cos⁡(θ)W = F \times d \times \cos(\theta)

    Where:

    • W = Work done
    • F = Force applied
    • d = Displacement
    • θ = Angle between force and displacement

    For work to be done, there must be displacement. If you apply a force but the object does not move (d=0d = 0), then the work done is zero.

    Explanation of Concepts
    • Option A: The man is applying an upward force to support the load, but the load is stationary (no displacement). Therefore, W=0W = 0.
    • Option B: When a boy climbs onto a table, he exerts a force to lift his body weight against gravity, and his body moves through a vertical distance (displacement). Since both force and displacement are present, work is done.
    • Option C: Pushing against a heavy table that does not move means the displacement is zero. Therefore, W=0W = 0.
    • Option D: Holding a pot of water requires force, but because the pot is held stationary, there is no displacement. Therefore, W=0W = 0.
    Step-by-Step Solution
    1. Identify the requirement: Work is only done when an object moves in the direction of the force applied.
    2. Evaluate each scenario: • A: No movement = No work. • B: Movement occurs as the boy climbs = Work is done. • C: No movement = No work. • D: No movement = No work.
    3. Conclusion: Only in option B does the application of force result in a change in position (displacement).
    Exam Tip

    Always remember the "Physics definition" of work: Work = Force × Distance. If you are tired from holding a heavy bag but you haven't moved an inch, a physicist would say you have done "zero work," even if your muscles feel exhausted! Look for the option where movement (displacement) actually occurs.

    AI can make mistakes. Report anything that looks wrong.

Frequently asked questions