31. Which one of the following statements is correct? A slab of ice kept in a room,
- A. does not radiate heat
- B. does not radiate heat but absorbs heat from the surrounding
- C. radiate heat but absorbs more heat from the surrounding
- D. radiate heat more than that absorbed by it from the surrounding
- Check Answer | Discussion
32. A space ship is from earth to moon and back. The greatest energy required for the spaceship is to overcome the difficulty in
- A. entering the earth's gravitational field
- B. entering the moon's lunar surface
- C. take off from the lunar surface
- D. take off the Earth's field
- Check Answer | Discussion
33. The cat survive fall from a height much more than human or any other animal. It is because the cat
- A. has elastic bones
- B. has thick and elastic skin
- C. can immediately adjust itself to land on all four paws and absorbs the impact of fall by bending
- D. None of the above
- Check Answer | Discussion
34. In a radioactive decay, a β- particle is emitted. This happens because
- A. aneutron is converted to proton and an electron is emitted
- B. valence electron is driven out of the outer shell
- C. by product of trasition of electron from inner to outer shell
- D. by product of transition of electron from outer to inner shell
- Check Answer | Discussion
35. For which one of the following cannot be emitted by radioactive substance during their decay?
- A. Rising of water from the roots of plant to its foliage
- B. Blotting of ink
- C. Rising of underground water
- D. Spread of water drop on a cotton cloth
- Check Answer | Discussion
36. Ball bearings are used in bicycles, cars, etc.,because
- A. the actual area of contact between the wheel and axle is increased
- B. the effective area of contact between the wheel and axle increased
- C. the effective area of contact between the wheel and axle is reduced
- D. None of the above statements is correct
- Check Answer | Discussion
37. When light enters from air to water,then its
- A. frequency increases and speed decreases
- B. frequency is same but the wavelength is smaller in water than in air
- C. frequency is same but the wavelength is greater in water than in air
- D. frequency is decreases but the wavelength is smaller in water than in air
- Check Answer | Discussion
38. In nuclear reaction which one of the following is conserved?
39. A planet is moving around the sun in an elliptical orbit. Its speed is
- A. same at all points of the orbit
- B. maximum when it is farthest from the sun
- C. maximum when it is nearest to the sun
- D. None of the above
- Check Answer | Discussion
40. A coin immersed in water pond appears to be raised when view from the top. what is this due to?
|
