21. | If the acceleration due to gravity of a planet is half the acceleration due to gravity of earth’s surface and radius of planet is half the radius of the earth, the mass of planet in terms of mass of earth is (a) (b) (c) (d) |

22. | The radii of the earth and the moon are in the ratio 10 : 1 while acceleration due to gravity on th eearth’s surface and moon’s surface are in the ratio 6 : 1. The ratio of escape velocities from earth’s surface to that of moon surface is (a) 10 : 1 (b) 6 : 1 (c) 1.66 : 1 (d) 7.74 : 1 |

23. | Acceleration due to gravity g in terms of mean density of Earth d (where R is radius of earth and G – universal gravitational constant) is (a) g = 4pR (b) g = (c) g = (d) g = |

24. | The dimensions of universal gravitational constant are (a) M (b) M (c) M L (d) M L |

25. | If R is radius of the earth and g the acceleration due to gravity on the earth’s surface, the mean density of the earth is (a) (b) (c) (d) |

Answer

21. Ans.: (d)

22. Ans.: (d)

23. Ans.: (d)

24. Ans.: (b)

25. Ans.: (c)