Physics 2020 Jamb Past Questions and Answers

Question 21 :

• JAMB 2020

A magnetic needle is suspended first at the earth's north magnetic pole and then at a point on the magnetic equator. The respective angles between the needle and the horizontal are

A. 0\(^o\) and 0\(^o\)
B. 60\(^o\) and 60\(^o\)
C. 90\(^o\) and 90\(^o\)
D. 90\(^o\) and 0\(^o\)

Question 22 :

• JAMB 2020

A hydrometer is an instrument for measuring the

A. A depth of water of water in a vessel
B. Relative density of a liquid by the method of flotation
C. Relative density of a liquid by finding the apparent loss in weight
D. Relative humidity of the air

Question 23 :

• JAMB 2020

Consider the three forces acting at O and in equilibrium as shown in the figure. Which of the following equations is/are CORRECT?
I. P\(_1\) cos \(\theta_1\) = p\(_1\) cos \(\theta_2\)
II. P\(_3\) = P\(_1\) cos \(\theta_4\) + P\(_2 cos_2\)
III. P\(_1 \sin \theta_1 = P_2 \sin \theta_2\)

A. I only
B. II only
C. III only
D. I, II and III only

Question 24 :

• JAMB 2020

The refractive index of a liquid is 1.5. If the velocity of light in vacuum is 3.0 x 10\(^8ms^{-1}\), the velocity of light in the liquid is

A. 1.5 x 10\(^8ms^{-1}\)
B. 2.0 x 10\(^8ms^{-1}\)
C. 3.0 x 10\(^8ms^{-1}\)
D. 4.5 x 10\(^8ms^{-1}\)

Question 25 :

• JAMB 2020

A ship travelling towards a cliff receives the echo of its whistle after 3.5 seconds. A short while later, it receives the echo after 2.5 seconds. If the speed of sound in air under the prevalling condition is 250ms -1, how much closer is the ship to the cliff?

A. 10m
B. 350m
C. 175m
D. 125m