1. A solid needle placed horizontally on the surface of the water floats due to

2. The swing of a spinning cricket ball in air can be explained on the basis of

3. Choose the incorrect statement from the following:

4. An observer moves towards a stationary plane mirror at a speed of 1 m/s. His image will move towards him at a speed of

5. In the following list of colours
1. Blue
2. Green
3. Red
4. Yellow Which are the three primary colours?

6. A man wearing spectacles, when working with a microscope

7. The heaviest among the inner planets is the

8. The mass of a body is different from its weight because
1. mass is a variable quantity whereas weight is constant
2. mass varies very little at different places whereas weight varies a lot
3. mass is constant but weight decreases as the body moves from the poles to the equator
4. mass is a measure of the quantity of matter whereas weight is a force Which of the above statements is/are correct?

9. If there were no atmosphere, the length of the day would

10. Let a tin capillary tube be replaced with another tube of insufficient length then we find that water

11. Critical reflection will take place if light travels from

12. Sound of frequency below 20 Hz are called

13. If a body is taken from the earth to the moon,
1. its mass will be different but weight will remain the same
2. both mass and weight will be different
3. its mass will remain the same but weight will be different
4. its density will remain unchanged Which of the above statements is/are correct?

14. An electrical appliance is earthed to
1. Protect the appliance against any damage
2. Prevent electric shocks
3. Avoid short-circuiting Which of the above is/are correct?

15. If water in a lake were to behave like other liquids, then in extremely cold weather it would freeze

16. A resonant system has a fundamental frequency of 100 Hz. If the next higher frequency that gives a resonance are 300 Hz and 500 Hz, the system could be

17. If two bodies, one heavy and one light, are acted upon by the same force for the same time, then both bodies acquire the same

18. The sun remains visible for some time after it actually sets below the horizon. This happens due to
1. atmospheric refraction
2. scattering of light
3. dispersion Which of the above statements is/are correct?

19. One feels cold after a dip in sea water due to

20. If the length of a pendulum is doubled, its frequency of oscillation is changed by a factor of

21. On heating a circular metallic disc with a circular hole at the centre, the diameter of the hole will

22. A man is sitting by the side of a large lake. He hears the utterances of bathers with their mouth close to water surface more clearly than if they were at same distance away on land. This effect is due to sound waves undergoing

23. Which of the following statements is/are correct?
1. The earth revolves around the sun in an elliptical orbit.
2. The sun always attracts the earth with the same force.

24. When a person enters a dark room from bright light, he is not able to see clearly for a little while because the

25. Atmospheric pressure is measured with a