Question

. The atmosphere is held to the Earth by

(a) gravity

(b) wind

(c) clouds

(d) Earth’s magnetic field

21. The force of attraction between two unit point masses separated by a unit distance is called

(a) gravitational potential

(b) acceleration due to gravity

(c) gravitational field

(d) universal gravitational constant

22. The weight of an object at the centre of the Earth of radius R is (NCERT Exemplar)

(a) zero

(b) infinite

(c) R times the weight at the surface of the Earth

(d) 1/R2

times the weight at surface of the Earth

23. An object weighs 10 N in air. When immersed fully in water, it weighs only 8 N. The weight of the liquid

displaced by the object will be

(a) 2 N

(b) 8 N

(c) 10 N

(d) 12 N

24. A girl stands on a box having 60 cm length, 40 cm breadth and 20 cm width in three ways. In which of the

following cases, pressure exerted by the box will be

(a) maximum when length and breadth form the base

(b) maximum when breadth and width form the base

(c) maximum when width and length form the base

(d) the same in all the above three cases

25. An apple falls from a tree because of gravitational attraction between the Earth and the apple. If F1 is the

magnitude of force exerted by the Earth on the apple and F2 is the magnitude of force exerted by the apple on the

Earth, then

(a) F1 is very much greater than F2

(b) F2 is very much greater than F1

(c) F1 is only a little greater than F2

(d) F1 and F1 are equal

26. The acceleration due to gravity on the Earth depends upon the

(a) mass of the body

(b) mass of the Earth

(c) shape and size of the body

(d) volume of the body​

Answer 1

Answer:

20.gravity

21.universal gravitational constant

22.zero

23. 2n

24.maximum when breadth and width form the base

25.c

26.b