Physics Past Questions and Answers

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:

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:

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:

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:

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