NEET Physics - New - Gravitation

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Question - 1

The kinetic energies of a planet in an elliptical orbit about the Sun, at positions A, B and Care KA, KBand KC respectively. AC is the major axis and SB is perpendicular to AC at the position of the Sun S as shown in the figure. Then

  • A KB > KA > KC
  • B KA> KB > KC
  • C KA< KB < KC
  • D KB < KA < KC

Question - 2

If the mass of the Sun were ten times smaller and the universal gravitational constant were ten times larger in magnitude, which of the following is not correct?

  • A Time period of a simple pendulum on the Earth would decrease
  • B Walking on the ground would become more difficult
  • C Raindrops will fall faster
  • D 'g' on the Earth will not change

Question - 3

The acceleration due to gravity at a height 1 km above the Earth is the same as at a depth d below the surface of Earth. Then

  • A d = 2km
  • B d = 1/2km
  • C d = 1km
  • D d = 3/2km

Question - 4

Starting from the centre of the Earth having radius R, the variation of g (acceleration due to gravity) is shown by

  • A  
  • B
  • C
  • D

Question - 5

A satellite of mass m is orbiting the earth (of radius R) at a height h from its surface. The total energy of the satellite in terms of got the value of acceleration due to gravity at the earth's surface, is

  • A mgoR2/2(R+h)
  • B -mgoR2/2(R+h)
  • C 2mgoR2/(R +h)
  • D -2 mgoR2/(R +h)

Question - 6

A remote sensing satellite of Earth revolves in a circular orbit at a height of 0.25x106 m above the surface of Earth. If Earth's radius is 6.38x 106 and g=9.8 m/s2, then the orbital speed of the satellite is:

  • A 7.76km/s
  • B 8.5km/s
  • C 9.13km/s
  • D 6.67km/s

Question - 7

A satellite S is moving in an elliptical orbit aroundthe Earth. The mass of the satellite is very small as compared to the mass of the Earth. Then,

  • A the angular momentum of S about the centre of the Earth changes in direction, but its magnitude remains constant
  • B the total mechanical energy of S varies periodically with time
  • C the linear momentum of S remains constant in magnitude
  • D the acceleration of S is always directed towards the centre of the Earth

Question - 8

Kepler's third law states that square of period of revolution (T) of a planet around the Sun, is proportional to third power of average distance r between the Sun and planet, i.e., T2=Kr3, here K is constant. If the masses of the Sun and planet are M and m respectively, then as per Newton's law of gravitation force of attraction between them is F=GMm/r2, here G is gravitational constant. The relation between G and K is described as

  • A GK=4π2
  • B GMK=4π2
  • C K=G
  • D K=l/G

Question - 9

A black hole is an object whose gravitational field is so strong that even light cannot escape from it. To what approximate radius would earth (mass = 5.98 x 1024 kg) have to be compressed to be a black hole?

  • A 10-9 m
  • B 10-6 m
  • C 10-2 m
  • D 100 m

Question - 10

The height at which the weight of a body becomes 1/16th, its weight on the surface of Earth (radius R), is:

  • A SR
  • B 15R
  • C 3R
  • D 4R