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Question Bank No: 1

1. A satellite is orbiting round the earth at a height h above the surface of the earth,if this distance h is increased,the time period of satellite will.

a)		decrease
b)		increase
c)		remain unaffected
d)		became zero

2. The planet of the elliptical orbit of a satellite revolving around earth passes through

a)		Centre of earth
b)		North pole
c)		South pole
d)		none of the above

3. The period of a satellite in a circular orbit around a plant is independent of

a)		The mass of the planet
b)		The radius of the planet
c)		The mass of the satellite
d)		All the three parameters a,b,c

4. The gravitational field due to a mass distribution is I = $\frac{C}{x^{2}}$ is x direction.Here C is constant .Taking the gravitational potential to be zero at infinity, potential at x is

a)		2 c/x
b)		c/x
c)		2 c/ $x^{2}$
d)		c/ ${2 x}^{2}$

5. Gravitational intensity at a place is given by

a)		G
b)		g
c)		mg
d)		none of the above

6. What will happen to the weight of the body at the south pole, if the earth stops rotating about its polar axis?

a)		no change
b)		increase
c)		decreases but does not become zero
d)		reduces to zero

7. At any point with in the interior of earth, the acceleration due to gravity varries with (distance between the centre of the earth and the point) as

a)		r
b)		$r^{2}$
c)		$γ r$
d)		$γ r^{2}$

8. What should be the speed with which the earth have to rotate on its axis, So that a person on the equator would weights (3/5)th as much as persent. Given equational radius is

a)		$\sqrt{2 g / 5 R}$
b)		$\sqrt{2 R / (5 g)}$
c)		2 $\sqrt{R} / 5 \sqrt{g}$
d)		2g/5R

9. The acceleration due to gravity on the moon is only one-sixth that of earth.If the earth and moon are assumed to have the same density, the ratio of the radii of earth and moon will be

a)		6
b)		$6^{1 / 3}$
c)		$6^{2 / 3}$
d)		$6^{2}$

10. A mass M is split into two parts m and (M-m) which are then seperated by a certain distance.The ratio m/m which maximizes the gravitational force between the parts is

a)		1:4
b)		1:3
c)		1:2
d)		1:1

11. The weight of a person on earth is 600 N.His weight on moon will appear as

a)		zero
b)		100N
c)		600 N
d)		3600 N

12. The tidal wave in the sea are primarly due to gravitational effect.

a)		earth on the sea
b)		sun on the earth
c)		earth on the moon
d)		moon on the earth

13. A simple pendilum is taken from the equator to the pole its period

a)		decreases
b)		increases
c)		remains the same
d)		none of the above

14. If earth revolves round the sun is one year if the distance between them becomes double.The new period of revolution will be

a)		$\frac{1}{2}$ year
b)		$2 \sqrt{2}$ years
c)		4 years
d)		8 years

15. A satellite of mass m moving around the earth of mass $M_{E}$ is circular orbit of radius R has angular momentum L.The rate of the area swept by the line joining the center

a)		$\frac{L}{2 m}$
b)		$\frac{L}{m}$
c)		$\frac{2 L}{m}$
d)		$\frac{2 L}{M_{E}}$

16. How much energy will be necessary for making a body of 500 kg escape from the earth radius of earth = 6.4 $\times 10^{6} cm$

a)		about 9.8 $\times 10^{6} J$
b)		about 6.4 $\times 10^{8} J$
c)		about 3.1 $\times 10^{10} J$
d)		about 27.4 $\times 10^{12} J$

17. The mass of the moon is about 1.2 % of the mass of the earth.Compared to the gravitational force the earth exerts on the moon. The gravitational force the moon exerts on earth

a)		is the same
b)		is smaller
c)		is greater
d)		varies with the phase

18. The value of g on the moon is $\frac{1}{6}$ th that on earth. A body weighing 60 kg on the earth has weight on the moon.

a)		20kg
b)		0
c)		360kg
d)		10kg

19. The period of revolution of planet A around the sun is 8 times that of B. The distance of A from the sum is how many times greater than that of B from the sun.

a)		2
b)		3
c)		4
d)		5

20. Who among the following gave first the experimental value of G.

a)		Cowendish
b)		Copernicus
c)		Broob Teylor
d)		None of these

21. A jet engine works on the principle of

a)		Conservation of mass
b)		Conservation of energy
c)		Conservation of linear momentum
d)		Conservation of angular momentum

22. Where wii it be profitable to purchase one kilogram sugar?

a)		at poles
b)		at equator
c)		at $45^{0}$ latitude
d)		at $40^{0}$ latitude

23. In a satellite if the time of revolution is T then K.E is proportional to

a)		$\frac{1}{T^{\frac{2}{3}}}$
b)		$\frac{1}{T}$
c)		$\frac{1}{T^{2}}$
d)		$\frac{1}{T^{3}}$

24. The rotation period of an earth satellite close to the surface of the earth is 83 minutes.The satellite in an orbit at a distance of three times earth radii its surface will be

a)		83 minutes
b)		83 $\times \sqrt{8}$ times
c)		664 minutes
d)		249 minutes

25. $V_{e}$ and $V_{p}$ denotes the escape velocity from the earth and another planet having twice the radius and same mean density as the earth.Then

a)		$V_{e}$ = $V_{p}$
b)		$V_{e}$ = $\frac{V_{p}}{2}$
c)		$V_{e}$ = ${2 V}_{p}$
d)		$V_{e}$ = $\frac{V_{p}}{4}$

26. The eccentricity of earth orbit is 0.0167.The ratio of its maximum and minimum speed around sun in this orbit will be

a)		1
b)		1.033
c)		2.507
d)		8.324

27. What is the ratio of gravitational mass and inertial mass

a)		$\frac{1}{2}$
b)		1
c)		2
d)		not fixed

28. Kepler 111 law $T^{2} \times R^{3}$ is a consequence of law of conservation of

a)		linear momentum
b)		angular momentum
c)		energy
d)		law of quantization of angular moment

29. A satellite of earth is revolving in a circular orbit with uniform velocity V.If gravitational force suddenly disappeared.The satellite will

a)		Continue to move with speed V along original orbit
b)		will fall to earth
c)		move with velocity V tangent to original orbit
d)		will fly away from earth due to absence of gravitational pull

30. The ratio of the radii of the planets P,and $P_{2}$ is a.The ratio of the escape velocities from them will be

a)		ab
b)		$\sqrt{ab}$
c)		$\sqrt{\frac{a}{b}}$
d)		$\sqrt{\frac{b}{a}}$

31. Weightlessness experienced while orbiting the earth in space ships is the result of

a)		inerba
b)		acceleration
c)		zero gravity
d)		centre of gravity

32. The time period of a second's pendulam in a satellite is

a)		Zero
b)		2
c)		infinity
d)		depends on mass

33. An artificial satelite is orbiting at a height of 1800km from earth's surface.The earth's radius is 6300km and g=10m/ $s^{2}$ on its surface.What is the radial acceleration.

a)		6m/ $s^{2}$
b)		7m/ $s^{2}$
c)		8m/ $s^{2}$
d)		9m/ $s^{2}$

34. The K.E.required to make a body move to infinity from the earth's surface is

a)		infinite
b)		2mg R
c)		$\frac{1}{2}$ mg R
d)		mg R

35. The escape velocity of a particle of mass m varries directly as

a)		$m^{2}$
b)		m
c)		$m^{0}$
d)		$m^{- 1}$

36. The ratio of the KE required to be given to the satellite to escape earth's gravitational field to the K.E. required to be given .So that the satellite moves in a circular orbit just above earth's atmosphere is

a)		one
b)		half
c)		two
d)		infinity

37. If v and E be the gravitational potential and gravitational field intensity at a distance x from the centre of a sphere,which of the following graphs is discontinuous?

a)		The graph of v versus x; for a solid sphere
b)		The graph of v versus x; for a hollow sphere
c)		The graph of E versus x; for a solid sphere
d)		The graph of E versus x; for a hollow shell

38. By what percent the energy of a satellite has to be increased to shift it from an orbit of radius r to 3r

a)		22.3%
b)		33.3%
c)		66.7%
d)		100%

39. Infinite number of masses each of 3 kg are placed along a straight line at the distances of 1m,2m,4m,8m...from a point 0 on the same line. If G is the universal gravitational field intensity at 0 is

a)		1.0G
b)		2.0G
c)		3.0G
d)		4.0G

40. Two bodies of masses $m_{1}$ and $m_{2}$ are placed at a distance r apart.Then at the position,where gravitational field due to them is zero,the gravitational potential is

a)		zero
b)		-G $\sqrt{m_{1}}$ /r
c)		-G $\sqrt{m_{2}}$ /r
d)		-G $(\sqrt{m_{1}} + {\sqrt{m_{2}})}^{2}$ /r

41. Two spheres of masses m ans M are situated in air and the gravitational force between them is F.The space around the masses is now filled with a liquid of specific gravity 3. The gravitational force will now be

a)		3F
b)		F
c)		F/3
d)		F/9

42. The accelaration due to gravity near the surface of the planet of radius R and density p is proportional to

a)		$\frac{p}{R^{2}}$
b)		${pR}^{2}$
c)		pR
d)		$\frac{p}{R}$

43. Two parties of mass $m_{1}$ and $m_{2}$ revolving in a circular path of radius $r_{1}$ and $r_{2}$ and taking same time for one complete revolution then ratio of their angular velocities will be

a)		$m_{1}$ : $m_{2}$
b)		$r_{1}$ : $r_{2}$
c)		1 : 1
d)		$m_{1}$ $r_{1}$ : $m_{2}$ $r_{2}$

44. A satellite is in an orbit around the earth.If its K.E. is doubled then

a)		it will rotate with greater speed
b)		it will fall on earth
c)		it will maintain its path
d)		it will escape out of earth's gravitational field

45. If g is the acceleration due to gravity on earth then increase in potential energy of a body of mass m upto a distance equal to twice the radius of the earth from the earth surface is

a)		$\frac{1}{2}$ mgR
b)		$\frac{2}{3}$ mgR
c)		$2$ mgR
d)		$\frac{1}{4}$ mgR

46. The escape velocity of an object from the earth depends upon the mass of the earth (M), its mean density ( $ρ$ ), its radius R and gravitational constant (G). Thus the formula for escape velocity is

a)		v = R $\sqrt{\frac{8 π}{3}}$ G $ρ$
b)		v = M $\sqrt{\frac{8 π}{3}}$ GR
c)		v = $\sqrt{2 GMR}$
d)		v = $\sqrt{\frac{2 GM}{R^{2}}}$

47. Which of the following statements is true?

a)		g is same at all places on the surface of the earth
b)		g has its maximum value at the equator
c)		g is less at the earth's surface than at a height above it or a depth below it
d)		g is greater at the poles than at the equator

48. A planet moves around the sun.At a point P,it is close to the sun at a distance $d_{1}$ and has speed $v_{1.}$ At another point P, When it is farthest from the sun at a distance $d_{2},$ its speed will be

a)		$d_{2} \frac{v_{1}}{d_{1}}$
b)		${d^{2}}_{2} \frac{v_{1}}{{d^{2}}_{1}}$
c)		${d^{2}}_{2} \frac{v_{1}}{{d^{2}}_{2}}$
d)		$d_{1} \frac{v_{1}}{d_{2}}$

49. Two satellites are orbiting around the earth in circular orbits of the same radius. One of them is 100 times greater in mass than the other.Their period of revolution are in the ratio

a)		1:1
b)		10:1
c)		100:1
d)		1:100

50. A mass is placed at a point B in the gravitational field of mass M, When the mass m is brought from B to near point A,its gravitational potentional energy will

a)		remain unchanged
b)		increase
c)		decrease
d)		become zero