Gravitation Mock Test – Class 11 Physics

1. The Moon does not fall straight down to Earth mainly because it has

2. The reduction in effective due to Earth’s rotation is maximum at the equator because there

3. Taking and , the escape speed from Earth is closest to

4. The graph of total mechanical energy for a projectile launched from Earth is used to classify its motion. If , , and , the corresponding ideal cases are

5. A student sees a graph of against below the axis and says, “The force must be repulsive because the energy is negative.” The best correction is that

6. For two spherical bodies separated by a gap, the distance in the gravitational force formula is measured

7. Two satellites of equal mass orbit the same planet in circular orbits of radii and . The ratio of their angular momenta is

8. A relation is used for a spacecraft at very large . As , the relation predicts

9. Assertion: Work done by gravity in moving a body from one point to another is independent of the path followed. Reason: Gravitational force is conservative.

10. For a point mass , the gravitational potential is . If is measured outward from the mass, is

11. The relation between escape speed and circular orbital speed at the same radius around the same planet is

12. A student claims, “A geostationary satellite stays fixed because Earth’s gravity is zero at that height.” The best evaluation is that the claim is

13. A circular satellite orbit has . After a maneuver, the satellite just escapes from the same radius. The minimum extra energy supplied by the engine is

14. A satellite in circular orbit has orbital speed . Its speed is increased to at the same radius. The smallest value of for escape is

15. A body is taken from Earth’s surface to a height above the surface. The increase in its gravitational potential energy is

16. A planet takes to orbit a star at radius . Another planet around the same star has orbital radius . Its period is

17. The mass of Earth can be estimated from surface gravity using

18. A planet moves from Point P near the Sun and later from Point Q far from the Sun, each during the same time interval. If the swept areas are equal, the arc length covered near Point P is generally

19. The missing SI unit in is

20. A satellite of mass is in a circular orbit of radius . Its radius is increased to by external work, and it finally moves in a circular orbit again. The external energy supplied is

21. Taking and , the time period of a satellite just above Earth’s surface is closest to

22. Two planets move around the same star in nearly circular orbits. Planet has orbital radius , and planet has orbital radius . The ratio is

23. Gravitational potential energy of two masses is taken as zero when their separation is

24. A satellite is in a circular orbit of radius . If its speed is suddenly reduced slightly while its position is unchanged, the immediate centripetal acceleration required for the old circular path becomes

25. A student applies at a point inside a uniform solid Earth with , using the full Earth mass . The correct repair is to use

26. A mass moves under gravity from point to point and then returns to along a different path. The total work done by gravitational force over the complete closed path is

27. The following table lists some common symbols in gravitation. Match each symbol with its usual meaning.

28. A planet has density and radius . Its surface gravity is proportional to

29. A graph of gravitational field magnitude versus distance from the centre of a uniform solid spherical planet is described. From to , the graph rises as a straight line; for , it falls as an inverse-square curve. This description is

30. A graph is drawn for a fixed arrangement of several source masses. The horizontal axis is the test mass , and the vertical axis is the net gravitational force magnitude on it. If the source masses and distances are unchanged, the graph should be

31. A satellite has speed in a circular orbit of radius . It is moved to another circular orbit where its speed is . The new orbital radius is

32. For a satellite of mass in a circular orbit of radius around a planet of mass , the correct starting equation for deriving Kepler’s third law is

33. Binding energy of a satellite in a circular orbit is best described as the energy required to

34. A student adds two gravitational pulls of and as without checking directions. If the two pulls are perpendicular, the actual resultant is

35. A planet has times Earth’s mass and times Earth’s radius. If Earth’s escape speed is , the planet’s escape speed is

36. Two planets have the same surface gravity , but planet has radius and planet has radius . The ratio of their escape speeds is

37. A dimensional test is applied to . The dimension of must be

38. A satellite’s circular orbit radius is increased. The correct combined change is that its orbital speed

39. A common error in geostationary-orbit calculations is to substitute the height directly for in . The correction is that should be

40. A student says, “Since increases toward as increases, gravity must point outward.” The best correction is that

41. A projectile is launched from Earth’s surface with speed and just reaches a maximum height above the surface. The required launch speed is

42. The table gives four arrangements of source masses around a test mass . Each source mass is at the same distance from .

The cases with zero net gravitational force on are

43. A test mass is placed between two fixed masses and on a straight line. If its distances from and are and respectively, the condition for zero net gravitational force on the test mass is

44. In the derivation of , the orbital speed is replaced by

45. A satellite of mass is in a circular orbit of radius . The energy that must be added to make it just escape from that orbit is

46. Near Earth’s surface, acceleration due to gravity means the acceleration of a body when it

47. A satellite is in a circular orbit of radius . Its kinetic energy is . If the satellite is shifted to a circular orbit of radius , its new kinetic energy is

48. A claim says, “A satellite in orbit has zero total energy because it is not falling to Earth.” The best evaluation is that the claim is

49. A dimensional check is made for the escape-speed expression . The dimension inside the square root is

50. The following table compares force and field for a test mass near a source mass .

The table shows that