Physics Past Questions

Which of the following conditions are necessary and sufficient for total internal reflection to take place at the boundary between two optical media?

I. Light is passing from optical denser medium to optically less dense medium

II. Light is passing from optically less dense medium to optically denser medium

III. Angle of incidence is greater than a certain critical value

IV. Angle of incidence is lesser  than a certain critical value

Which of the following statements about defects of vision is/are CORRECT? 

I. For a long sighted person, close objects appear blurred

II. For a short sighted person, distant objects appear blurred 

III. Short sight is corrected by using a pair of converging lenses 

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?

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 

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 hydrometer is an instrument for measuring the 

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 

Two mirrors of the same length are arranges as show in the diagram. A ray of light NO strikes the system at O and emerges along PQ. The emergent ray has been deviated through 

A convex mirror is used as a driving mirror because 

I. its image is erect     

II. It has a large field of view

III. It has a long focal length 

Identify the CORRECT statement(s) 

When a sound wave passes from air into water its 

One of the following readings represents the measurement of the length of a metal rod using vernier callipers. Taking the reading accuracy into consideration, the most likely one is 

A solid weighs 4.8g in air, 2.8g in water and 3.2g in Kerosine. The ratio of density of the solid to that of the kerosine is 

A transformer has 300 turns of wire in the primary coil and 30 turns in the secondary coil. If the input voltage is 100 volts, the output voltage is 

Tha mass of a proton is approximately equal to that of 

What is the cost of running five 50W lamps and four 100W lamps for 10 hours if electrical energy costs 2 Kobo per KWh?

Which of the following can be described as high tension transmission? 

If a source of solid is moving, a stationary listener will hear a sound of different frequency. This is called?

Natural radioactivity consists of emission?

Which of the following statements on the use of X-rays is incorrect? X-rays are used