# Jamb Physics Questions and Answers for 2020 (CBT)

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Welcome to JAMB Physics questions and answers for 2020/2021 CBT exams. I believe you are one of the candidates searching online for JAMB 2020 Physics questions and answers. If that’s true, here is the right place for you.

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It is very important to understand some key things in physics. For instance, you should know that when a body starts from rest, its initial velocity is zero (u = 0) and when it comes to rest, its final velocity is zero (v = 0).

JAMB has the areas that it repeats questions annually. Knowing those areas would help you concentrated on what you may likely see in your Jamb exams.

There are some special topics in physics that Jamb cannot set questions without including them. Those topics are listed hereunder:

1. Optics
2. Energy Quantization
3. Basic Electronics
4. Electric Field
5. Magnetism
6. Waves
7. Motion

## JAMB PHYSICS QUESTIONS AND ANSWERS FOR 2020/2021 CBT EXAMS

The equation X15062 => Y150 63 + -1 + energy, represents

A. Alpha decay

B. Beta-decay

C. Gamma decay

D. Photon emission

2. The ice and steam points of a thermometer are 20mm and 100mm respectively. A temperature of 75 degree celsius corresponds to Y mm on the thermometer. What is Y?

A. 100 mm

B. 70 mm

C. 80 mm

D. 60 mm

3. When a yellow card is observed through a blue glass, the card would appear as

A. Black

B. Green

C. Red

D. White

4. In a nuclear plant, the final mass of the products is 6.32×10^-27kg, while the initial mass of the reactant is 6.30×10^-27kg, the energy released in the process is (speed of light in vacuum 3.0×10^8m/s, 1eV = 1.6×10^-19J)

A. 11.25meV

B. 11.25 MJ

C. 12.25MJ

D. 12.25meV

5. A 1.5kg stone was thrown vertically upward with an initial velocity of 42m/s, What is the potential energy of the stone at the highest point reached.

A. 3.15J

B. 13.23J

C. 26.46J

D. 63.00J

6. 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 of P to Q is

A. 1:4

B. 4:1

C. 1:1

D. 2:1

7. The following statements were made by some students describing what happened during the determination of the melting point of solids

1. The temperature of the solid was constant until melting started

2. The temperature of the solid rose until melting started

3. During melting, the temperature was rising

4. During melting, the temperature was constant

5. The temperature continued to rise after all the solid had melted.

6. The temperature stopped rising after all the solid had melted. Which of the following gives correct statements in the right order?

A. 2, 4 and 5

B. 2, 3 and 6

C. 1, 3 and 6

D. 1, 3 and 5

8. A silver spoon and a wooden spoon are both at room temperature. The silver spoon is cooler to touch because silver

A. has a greater density

B. can be polished

C. is a less absorbent material than wood

D. is a better conductor of heat

9. A long jumper leaves the ground at an angle of20 degrees above the horizontal and at a speed of 11m/s. How far does it jump in the horizontal direction?

A. 0.38m

B. 7.49m

C. 8.45m

D. 0m

10. The thrust due to hydrostatic pressure alone on the bottom of a fish tank which is 60cm x 40cm when the depth of water is 30cm is?

A. 8N

B. 12N

C. 720N

D. 24N

11. An object of mass 50g is suspended from the end of a spiral spring of force constant 0.5N/m, the body is set into simple harmonic motion with 0.3m displacement. The period of the motion is

A. 1.00s

B. 1.99s

C.3.00s

D. 2.5s

12. If 21g of alcohol of density 0.7gcm^-3 is mixed with 10g of water, what would be the density of the resulting mixture?

A. 780gcm^-3

B. 0.78gcm^-3

C. 30gcm^-3

D. 10gcm^-3

13. Two masses 50g and 70g are suspended from the respective ends of a light metre rule, the centre of gravity of the system is

A. 50.0cm

B. 52.3cm

C. 70.2cm

D. 80.4cm

14. A transformer which can produce 10V from a 240V a.c supply has an efficiency of 60%. If the current in the secondary winding coil is 15A, the current in the primary coil is

A. 15.0 A

B. 1.04 A

C. 16.04 A

D. 13.96 A

15. The acceleration due to gravity

A. increases with increasing altitude

B. decreases with increasing altitude

C. increases with an increase in the square of the altitude

D. is not affected by the altitude

16. A nail is pulled from a wall with a string tied to the nail. If the string is inclined at an angle of 30 degrees to the wall and the tension in the string is 50N, the effective force used in pulling the nail is:

A. 25N

B. 25 SQRT(3)

C. 50 N

D. 50 SQRT(3)

17. The electromagnetic waves that are sensitive to temperature changes are

A. Ultra-violet rays

B. Gamma-rays

C. Infra-red rays

D. X-rays

18. A boy of mass m, suspended from a spring, is put into simple harmonic motion. If the motion has amplitude A and the spring constant k, the maximum potential energy of the mass is

A. KA

B. 0.5 kA^2

C. MkA

D. kA^2/m

19. A transformer connected to a 240V a.c, source has 500 turns in its primary winding and 25 turns in its secondary winding. Calculate the e.m.f induced in the secondary winding

A. 9.6 V

B. 12.0 V

C. 120.0 V

D. 52.1 V

20. The fundamental frequency of vibration of a sonometer wire may be halved by

A. doubling the length of the wire

B. doubling the mass of the wire

C. reducing the tension by half

D. reducing the absolute temperature

21. A car of mass 800kg attains a speed of 25m/s in 20 secs. The power developed in the engine is

A. 25 x 104 W

B. 50 x 104 W

C. 25 x 106W

D. 50 x 106 W

22. When the brakes in a car are applied, the frictional force on the tyres

A. is a disadvantage because it is in the direction of the motion of the car

B. is a disadvantage because it is in the opposite direction of the motion of the car

C. is an advantage because it is in the direction of the motion of the car

D. is an advantage because it is in the opposite direction of the motion of the car

23. If the stress on a wire is 107NM-2 and the wire is stretched from its original length of 10.00 cm to 10.05 cm. The young’s modulus of the wire is

A. 5.0 x 104 Nm-2

B. 5 .0 x 105 Nm-2

C. 2.0 x 108 Nm-2

D. 2.0 x 109 Nm-2

24. A solid weigh 10 .00 N in air, 6 N when fully immersed in water and 7.0 N when fully immersed in a liquid X. Calculate the relative density of the liquid, X.

A. 5/3

B. 4/3

3. 3/4

D. 7/10

25. When the temperature of liquid increases, its surface tension

A. Decreases

B. Increases

C. Remain Constant

D. Increases then decrease

26. A gas at a volume of Vo in a container at pressure Po is compressed to one-fifth of its volume. What will be its pressure if the magnitude of its original temperature T is constant?

A. Po/5

B. 4Po/5

C. Po

D. 5Po

27. A waterfall is 420m high, calculate the difference in temperature of the water between the top and bottom of the waterfall assuming no heat is lost. [speciﬁc heat capacity of water = 4.20 * 103Jkg-1K-1g=10-2]

A. 10° C

B. 42.0° C

C. 4.2° C

D.1° C

28. A body when slightly displaced is said to be in neutral equilibrium only if it tends to

A. comes to rest in a new position with the centre of gravity and height remaining unchanged

C.remain in its displaced position

D. move further away from its original position while its centre of mass changes

29. A string of length 5m 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 = 1Oms-2]

A. 0.04m

B. 0.12m

C. 0.01m

D. 0.08m

30. Which of the following has negligible mass?

A. Protons

B. Gamma rays

C. Beta particles

D. Alpha particles

31. How can energy loss be minimized through Eddy-current?

A. By using a high resistance wire

B. By using insulated soft iron wires

C. By using low resistance wires

D. By using turns of wires

32. Calculate the upthrust on an object of volume 50cm3 which is immersed in a liquid of density 103kgm-3. [g = 10ms-2]

A. 0.8N

B. 2.5N

C. 0.5N

D. 1.0N

33. Which of the following would appear when a white screen is illuminated by red and green light?

A. Red

B. Purple

C. Yellow

D. Green

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

A. II and III only

B. I, II and IIII

C. I and II only

D. I and III only

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

A. 18.57 NC-1

B. 53.06 NC-1

C. 2.28 NC-1

D. 0.80 NC-1

36. The distance between the image and the object in a plane mirror is 40cm if the distance of the object is reduced by 9.2cm, what is the distance of the object from the mirror?

A. 17.50m

B.15.50m

C.18.50m

D.16.50m

37. Find the potential energy of an object of mass 10kg placed on a building floor 10m above the ground level. [g=10m-2]

A. 10,000J

B. 5,000J

C. 100J

D. 1,000J

38. 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.

A. 30 cm3

B. 40 cm3

C. 50 cm3

D. 20 cm3

39. The product PV where P is pressure and V is volume has the same unit as

A. impulse

B. power

C. force

D. work

40. What is the cost of running seven 40W lamps and five 80W lamps for 12 hours if the electrical energy cost ₦ 7.00kWk?

A. ₦ 80.00

B. ₦ 45.36

C. ₦ 65.00

D. ₦ 57.12

The above questions are JAMB Physics questions and answers for 2020/2021 CBT exams

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JAMB MATHEMATICS QUESTIONS AND ANSWERS FOR 2020 (CBT)