2012 JAMB Physics Past Questions & Answers

Question 1

Disperson of white light is the ability of white light to

Accepted Answer

D. separate to its component colours

Answer

A. penetrate air, water and glass

Answer

B. move in a straight line

Answer

C. move around corners

Question 2

A pinhole camera is placed 300m in front of a building so that the image is formed on a screen 5cm from the the pinhole. If the image is 2.5cm high, the height of the building will be

Accepted Answer

D. 150m

Answer

A. 25m

Answer

B. 50m

Answer

C. 100m

Question 3

The fuse in an electric device is always connected to the

Accepted Answer

C. live side of an electric supply

Answer

A. neutral side of an electric supply

Answer

B. earth side of an electric supply

Answer

D. terminal side of an electric supply

Question 4

If a load of 1 kg stretches a cord by 1.2cm, what is the force constant of the cord? {g=10$ms^{-2}$}

Accepted Answer

B. 833$Nm^{-1}$

Answer

A. 866$Nm^{-1}$

Answer

C. 769$Nm^{-1}$

Answer

D. 667$Nm^{-1}$

Question 5

I. It is a rapid, constant and irregular motion of tiny particles. II. It gives evidence that tiny particles of matter called molecules exist. III. It takes place only in gases. IV. It gives evidence that molecules are in a constant state of random motion. which of the combinations above is correct about Brownian notion?

Accepted Answer

D. l, ll and lV only

Answer

A. I,II and III only

Answer

B. II,III and IV only

Answer

C. I,III and lV only

Question 6

After reflection from the concave mirror, rays of light from the sun converges

Accepted Answer

B. at the focus

Answer

A. at the radius of curvature

Answer

C. beyond the radius of curvature

Answer

D. between the focus and radius of curvature

Question 7

The current output from of an a.c. source is given as I = 10 sin to t. The d.c equivalent of the current is

Accepted Answer

B. 7.1A

Answer

A. 5.0A

Answer

C. 10.0A

Answer

D. 14.1A

Question 8

The equation of a wave traveling in a horizontal direction is expressed as y = 15 sin $\frac{2\pi}{5}$ (60t - x). What is its wavelength?

Accepted Answer

C. 5m

Answer

A. 60m

Answer

B. 15m

Answer

D. 2m

Question 9

The process of detecting a pin mistakenly swallowed by a child is X-ray

Accepted Answer

A. Diagnosis

Answer

B. Therapy

Answer

C. Crystallography

Answer

D. Mammography

Question 10

The characteristic of a vibration that determines its intensity is the

Accepted Answer

D. Amplitude

Answer

A. Frequency

Answer

B. Overtone

Answer

C. Wavelength

Question 11

A car starts from rest and moves with a uniform acceleration of 30$ms^{-2}$ for 20s. Calculate the distance covered at the end of the motion

Accepted Answer

A. 6km

Answer

B. 12km

Answer

C. 18km

Answer

D. 24km

Question 12

Which of the following CANNOT be deflected by both electric and magnetic fields?

Accepted Answer

A. Gamma rays

Answer

B. Alpha particles

Answer

C. Wave particles

Answer

D. Beta particles

Question 13

The use of lenses is Not applicable in the

Accepted Answer

C. periscope

Answer

A. projector

Answer

B. human eye

Answer

D. telescope

Question 14

The magnification of an object 2cm tall when placed 10cm in front of a plane mirror is

Accepted Answer

B. 1.0

Answer

A. 6.0

Answer

C. 0.7

Answer

D. 0.6

Question 15

A balloon whose volume is 300m3 is filled with hydrogen. If the density of air is 1.3 kgm-3, find the upthrust on the balloon. [g = 10$ms^{-2}$]

Accepted Answer

C. 3900N

Answer

A. 3000N

Answer

B. 3800N

Answer

D. 4200N

Question 16

A particle carrying a charge of 1. 0 x 10-8C enters a magnetic field at 3.0x 10-2 ms -1 at right angles to the field. If the force on this particle is 1.8 x 10-8N, what is the magnitude of the field?

Accepted Answer

B. 6.0x10T

Answer

A. 6.0x10-1T

Answer

C. 6.0x10-3T

Answer

D. 6.0x10-4T

Question 17

Calculate the total distance covered by a train before coming to rest if its initial speed is 30$ms^{-1}$ with a constant retardation of 0.1m-2

Accepted Answer

B. 4500m

Answer

A. 5500m

Answer

C. 4200m

Answer

D. 3000m

Question 18

An object of mass 20kg slides down an inclined plane at an angle of 30o to the horizontal. The coefficient of static friction is? [g = 10$ms^{-2}$]

Accepted Answer

D. 0.6

Answer

A. 0.2

Answer

B. 0.3

Answer

C. 0.5

Question 19

If a freely suspended object is pulled to one side and released, it oscillates about the point of suspension because the

Accepted Answer

A. acceleration is directly proportional to the displacement

Answer

B. motion is directed away from the equilibrium point

Answer

C. acceleration is directly proportional to the square of the displacement

Answer

D. velocity is minimum at the equilibrium ponit

Question 20

2000cm3 of a gas is collected at 27oC and 700mmHg. What is the volume of the gas at standard temperature and pressure?

Accepted Answer

C. 1676.3cm3

Answer

A. 1896.5cm3

Answer

B. 1767.3cm3

Answer

D. 1456.5cm3

Question 21

Clinical thermometers are examples of

Accepted Answer

D. mercury- in - glass thermometer

Answer

A. pressure gas thermometer

Answer

B. resistance thermometer

Answer

C. alcohol thermometer

Question 22

The pressure at any point in a liquid at rest depends only on the

Accepted Answer

A. depth and the density

Answer

B. mass and the volume

Answer

C. quantity and the surface area

Answer

D. surface area and the viscosity

Question 23

I. Small size. II. Low power requirement III. Not easily damaged by high temperature IV. Highly durable. Which of the above are the advantages of semiconductors?

Accepted Answer

C. l, II and lV only

Answer

A. I,II and lll only

Answer

B. ll,lll and lV only

Answer

D. l, ll, lll and lV

Question 24

Which of the following is NOT a factor that can increase the rate of evaporation of water in a lake?

Accepted Answer

A. increase in the pressure of the atmosphere

Answer

B. rise in temperature

Answer

C. increase in the average speed of the molecules of water

Answer

D. increase in the kinetic energy of the molecules of water

Question 25

If a reverse-biased voltage is applied across a p-n junction, the depletion layer width is

Accepted Answer

A. increased

Answer

B. decreased

Answer

C. constant

Answer

D. halved

Question 26

A piece of radioactive material contains 1000 atmos. If its half -life is 20seconds, the time taken for 125 atoms to remain is

Accepted Answer

D. 60 seconds

Answer

A. 20 seconds

Answer

B. 40 seconds

Answer

C. 80 seconds

Question 27

A glass block of thickness 10cm is placed on an object. If an observer views the object vertically, the displacement of the object is

Accepted Answer

A. 3.33cm

Answer

B. 5.00cm

Answer

C. 6.67cm

Answer

D. 8.50cm

Question 28

Where can a man place his face to get an enlarged image when using a concave mirror to shave?

Accepted Answer

C. Between the principal focus and the pole

Answer

A. Between the centre of curvature and the principal focus

Answer

B. At the principal focus

Answer

D. At the centre of curvature

Question 29

A rocket is fired from the earth's surface to a distant planet. By Newton's law of universal gravitation, the force F will

Accepted Answer

A. increase as r reduces

Answer

B. increase as G varies

Answer

C. remains constant

Answer

D. increases as r increases

Question 30

An object moves in a circular path of radius 0.5m with a speed of 1$ms^{-1}$ What is its angular velocity?

Accepted Answer

C. 2 rads-1

Answer

A. 8 rads-1

Answer

B. 4 rads-1

Answer

D. 1 rads-1

Question 31

Which of the following factors will affect the velocity of sound?

Accepted Answer

C. Wind travelling in the same direction of the sound

Answer

A. An increase in the pitch of the sound

Answer

B. An increase in the loudness of the sound

Answer

D. A change in the atmospheric pressure at constant temperature

Question 32

Calculate the temperature change when 500J of heat is supplied to 100g of water [specific heat capacity of water = 4200JKg$^{-1}$k$^{-1}$]

Accepted Answer

C. 1.2oC

Answer

A. 12.1oC

Answer

B. 2.1oC

Answer

D. 0.1oC

Question 33

In order to remove the error of parallax when taking measurements with a metre rule, the eye should be focused

Accepted Answer

C. vertically downwards on the markings

Answer

A. slantingly towards the right on the markings

Answer

B. slantingly towards the left on the markings

Answer

D. vertically upwards on the markings

Question 34

A newly charged 12V accumulator can easily start a car whereas eight new dry cells in series with a effective e.m.f. of 12V cannot start the same car because

Accepted Answer

B. The current capacity is low

Answer

A. The current capacity is high

Answer

C. it cannot be re-charged

Answer

D. it cannot easily be connected to a car

Question 35

The quantity of heat energy required to melt completely 1 kg of ice at - 30oC is [latent heat of fusion = 3.5 x 10 5Jkg -1, specific heat capacity of ice = 2.1x10 3Jkg -1K -1]

Accepted Answer

B. 4.13x10 5J

Answer

A. 4.13x10 6J

Answer

C. 3.56x10 4J

Answer

D. 3.56x10 2J

Question 36

A load is pulled at a uniform speed along a horizontal floor by a rope at 45o to floor. If the force in the rope is 1500N, what is the frictional force on the load ?

Accepted Answer

D. 1061N

Answer

A. 1524N

Answer

B. 1350N

Answer

C. 1260N

Question 37

An object of volume 1 m 3 and mass 2kg is totally immersed in a liquid of density 1 kgm-3 . Calculate its apparent weight.

Accepted Answer

B. 10N

Answer

A. 20N

Answer

C. 2N

Answer

D. 1 N

Question 38

A block and tackle is used to raise a load of 250N through a vertical distance of 30m. What is the efficiency of the system if the work done against friction is 1500J?

Accepted Answer

C. 83.3%

Answer

A. 62.5%

Answer

B. 73.3%

Answer

D. 94.3%

Question 39

Two metals P and Q are heated through the same temperature difference. If the ratio of the linear expansivities of P to Q is 2:3 and the ratio of their length is 3: 4 respectively, the ratio of the increase in lengths of P to Q is

Accepted Answer

A. 1:2

Answer

B. 2:1

Answer

C. 8:9

Answer

D. 9:8

Question 40

I. Rays of light travel from a less dense medium to a denser medium. II. The Angle of incidence is greater than critical angle. III. Rays of light travel from a denser medium to a less dense medium. Which of the statements above are conditions for total internal reflection to occur?

Accepted Answer

C. II & III only

Answer

A. I & II only

Answer

B. I & III only

Answer

D. II only

Question 41

A conductor of length 1m moves with a velocity of 50$ms^{-1}$ at an angle of 30o to the direction of a uniform magnetic field of flux density 1.5Wbm-2. What is the e.m.f induced in the conductor?

Accepted Answer

A. 37.5V

Answer

B. 50.5V

Answer

C. 75.0V

Answer

D. 80.5V

Question 42

The p-n junction diodes can act as rectifiers because they

Accepted Answer

A. conduct current when forward-biased

Answer

B. conduct current when reverse-biased

Answer

C. block current when forward-biased

Answer

D. conduct current in both directions

2012 JAMB Physics Past Questions

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