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(a) It moves in a plane containing the Greenwich meridian (b) It moves in a plane perpendicular to the celestial equatorial plane (c) Its height above the earth’s surface is about the same as the radius of the earth (d) …

35. The periodic time of a communication satellite is

(a) 6 hours (b) 12 hours (c) 18 hours (d) 24 hours Answer: d (11)

In the following four periods

(i) Time of revolution of a satellite just above the earth’s surface(Tst) (ii) Period of oscillation of mass inside the tunnel bored along the diameter of the earth(Tma) (iii) Period of simple pendulum having a length equal to the earth’s …

A satellite is to revolve round the earth in a circle of radius 8000 km. The speed at which this satellite be projected into an orbit, will beA satellite is to revolve round the earth in a circle of radius 8000 km. The speed at which this satellite be projected into an orbit, will be

(a) 3 km/s (b) 16 km/s (c) 7.15km/s (d) …

44. A satellite is launched into a circular orbit of radius ‘R’ around earth while a second satellite is launched into an orbit of radius 1.02 R. The percentage difference in the time periods of the two satellites is

(a) 0.7 (b) 1.0 (c) 1.5 (d) 3 Answer: d (43)

42. A geo-stationary satellite is orbiting the earth at a height of 6 R above the surface of earth, R being the radius of earth. The time period of another satellite at a height of 2.5 R from the surface of earth is

(a) 10 hr (b) (6/√2) hr (c) 6 hr (d) 6√2hr Answer: d (4)

40. Periodic time of a satellite revolving above Earth’s surface at a height equal to R, radius of Earth, is [g is acceleration due to gravity at Earth’s surface]

(a) 2π√2R/ g (b) 4√2π√R/g (c) 2π√R/ g (d) 8π√R/ g Answer:b (7)

39. If Gravitational constant is decreasing in time, what will remain unchanged in case of a satellite orbiting around earth

(a) Time period (b) Orbiting radius (c) Tangential velocity (d) Angular velocity Answer: c (3)

38. The distance of a geo-stationary satellite from the centre of the earth (Radius R = 6400 km) is nearest to

(a) 5 R (b) 7 R (c) 10 R (d) 18 R Answer: b (3)

91. A load W produces an extension of 1mm in a thread of radius r. Now if the load is made 4W and radius is made 2r all other things remaining same, the extension will become

(a) 4 mm (b) 16 mm (c) 1 mm (d) 0.25 mm Answer-c (22)

92. The units of Young ‘s modulus of elasticity are

(a) Nm-1 (b) N-m (c) Nm-2 …

89. Under elastic limit the stress is

(a) Inversely, proportional to strain (b) Directly proportional to strain (c) Square root of strain (d) Independent of strain Answer-b (16)

88. The modulus of elasticity is dimensionally equivalent to

(a) Surface tension (b) Stress (c) Strain (d) None of these Answer-b (16)

87. A force F is applied on the wire of radius r and length L and change in the length of wire is l. If the same force F is applied on the wire of the same material and radius 2r and length 2L, Then the change in length of the other wire is

(a) l (b) 2l (c) l/2 (d) 4l Answer-c (10)

86. In solids, inter-atomic forces are

(a) Totally repulsive (b) Totally attractive (c) Combination of (a) and (b) (d) None of these Answer-c (5)

Three rods each of length L and mass M are placed along X, Y and Z-axes in such a way that one end of each of the rod is at the origin. The moment of inertia of this system about Z axis is

(a) 2ML2/3 (b) 4 ML2/3 (c) 5 ML2/3 (d) ML2/3 Ans. a (12)

The ratio of the K.E. 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 atmosphere is

(a) One (b) Two (c) Half (d) Infinity Answer: b (4)

19. Let be the moment of inertia of an uniform square plate about an axis AB that passes through its centre and is parallel to two of its sides. CD is a line in the plane of the plate that passes through the centre of the plate and makes an angle θ with AB . The moment of inertia of the plate about the axis CD is then equal to

(a) l (b) l sin2θ (c) l cos2θ …

Moment of inertia of a uniform circular disc about a diameter is I. Its moment of inertia about an axis perpendicular to its plane and passing through a point on its rim will be

(a) 5 I (b) 6 I (c) 3 I (d) 4 I Ans. b (6)

An astronaut orbiting the earth in a circular orbit 120 km above the surface of earth, gently drops a spoon out of space-ship. The spoon will

(a) Fall vertically down to the earth (b) Move towards the moon (c) Will move along with space-ship (d) Will move in an irregular way then fall down to earth Answer: c (3)

A satellite which is geostationary in a particular orbit is taken to another orbit. Its distance from the centre of earth in new orbit is 2 times that of the earlier orbit. The time period in the second orbit is

(a) 4.8 hours (b) 48√2 hours (c) 24 hours (d) 24 √2 hours Answer: b (3)

80. The extension of a wire by the application of load is 3 mm. The extension in a wire of the same material and length but half the radius by the same load is

(a) 12 mm (b) 0.75 mm (c) 15 mm (d) 6 mm Answer-a (37)

85. An iron rod of length 2m and cross section area of , stretched by 0.5 mm, when a mass of 250 kg is hung from its lower end. Young’s modulus of the iron rod is

(a) 19.6×1010 N/m2 (b) 19.6×1015 N/m2 (c) 19.6×1018 N/m2 (d) 19.6×1020 N/m2 Answera-a (7)

84. Which of the following affects the elasticity of a substance

(a) Hammering and annealing (b) Change in temperature (c) Impurity in substance (d) All of these Answer-d (5)

5. Consider a satellite going round the earth in an orbit. Which of the following statements is wrong

(a) It is a freely falling body (b) It suffers no acceleration (c) It is moving with a constant speed (d) Its angular momentum remains constant Answer: b (6)

83. If a spring is extended to length l, then according to Hook’s law

(a) F=kl (b) F=k/l (c) F=k 2l …

An earth satellite of mass m revolves in a circular orbit at a height h from the surface of the earth. R is the radius of the earth and g is acceleration due to gravity at the surface of the earth. The velocity of the satellite in the orbit is given by

(a) gR2/R+h (b) gR (c) gR/R+h (d) √gR2/R+h Answer: d (7)

Select the correct statement from the following

(a) The orbital velocity of a satellite increases with the radius of the orbit (b) Escape velocity of a particle from the surface of the earth depends on the speed with which it is fired (c) The time period of …