JEE Questions for Physics Gravitation Quiz 13 - MCQExams.com

The escape velocity from the earth is about 11 km/second. The escape velocity from a planet having twice the radius and the same mean density as the earth, is
  • 22 km/sec
  • 11 km/sec
  • 5.5 km/sec
  • 15.5 km/sec
If g is the acceleration due to gravity at the earth\'s surface and r is the radius of the earth, the escape velocity for the body to escape out of earth\'s gravitational field is
  • gr
  • √2gr
  • g/r
  • r/g
Two small and heavy spheres, each of mass M, are placed a distance r apart on a horizontal surface. The gravitational potential at the mid-point on the line joining the centre of the spheres is
  • Zero
  • 2)
    Physics-Gravitation-74835.png

  • Physics-Gravitation-74836.png

  • Physics-Gravitation-74837.png
The escape velocity of a planet having mass 6 times and radius 2 times as that of earth is

  • Physics-Gravitation-74839.png
  • 2)
    Physics-Gravitation-74840.png

  • Physics-Gravitation-74841.png

  • Physics-Gravitation-74842.png
The escape velocity of a body on the surface of the earth is 11.2 km/s. If the earth\'s mass increases to twice its present value and the radius of the earth becomes half, the escape velocity would become
  • 5.6 km/s
  • 11.2 km/s (remain unchanged)
  • 22.4 km/s
  • 44.8 km/s
Given mass of the moon is 1/81of the mass of the earthand corresponding radius is 1/4 of the earth. If escape velocity on the earth surface is 11.2 km/s, the value of same on the surface of the moon is
  • 0.14 km/s
  • 0.5 km/s
  • 2.5 km/s
  • 5 km/s
The earth is assumed to be a sphere of radius R. A platform is arranged at a height R from the surface of the earth. The escape velocity of a body from this platform is fv, where v is its escape velocity from the surface of the earth. The value of f is

  • Physics-Gravitation-74846.png
  • 2)
    Physics-Gravitation-74847.png

  • Physics-Gravitation-74848.png

  • Physics-Gravitation-74849.png
If the radius of a planet is R and its density is ρ, the escape velocity from its surface will be

  • Physics-Gravitation-74851.png
  • 2)
    Physics-Gravitation-74852.png

  • Physics-Gravitation-74853.png

  • Physics-Gravitation-74854.png
What is the escape velocity for a body on the surface of a planet on which the acceleration due to gravity is (3.1)2ms–2 and whose radius is 8100 km?
  • 2790 km. s–1
  • 27.9 km. s–1

  • Physics-Gravitation-74856.png

  • Physics-Gravitation-74857.png
Three particles each of mass m are kept at vertices of an equilateral triangle of side L. The gravitational field at centre due to these particles is
  • Zero
  • 2)
    Physics-Gravitation-74859.png

  • Physics-Gravitation-74860.png

  • Physics-Gravitation-74861.png
Escape velocity on the surface of earth is 11.2 km/s. Escape velocity from a planet whose mass is the same as that of earth and radius 1/4 that of earth is
  • 2.8 km/s
  • 15.6 km/s
  • 22.4 km/s
  • 44.8 km/s
The velocity with which a projectile must be fired so that it escapes earth\'s gravitation does not depend on
  • Mass of the earth
  • Mass of the projectile
  • Radius of the projectile's orbit
  • Gravitational constant
If V, R and g denote respectively the escape velocity from the surface of the earth radius of the earth and acceleration due to gravity, then the correct equation is

  • Physics-Gravitation-74864.png
  • 2)
    Physics-Gravitation-74865.png

  • Physics-Gravitation-74866.png

  • Physics-Gravitation-74867.png
For a satellite moving in an orbit around the earth, the ratio of kinetic energy to potential energy is
  • 2
  • 2)
    Physics-Gravitation-74868.png

  • Physics-Gravitation-74869.png

  • Physics-Gravitation-74870.png
A particle of mass 10 g is kept on the surface of a uniform sphere of mass 100 kg and radius 10 cm. Find the work to be done against the gravitational force between them to take the particle far away from the sphere (you may take G = 6.67 × 10–11Nm2/kg2)
  • 6.67 × 10–9 J
  • 6.67 × 10–10 J
  • 13.34 × 10–10 J
  • 3.33 × 10–10 J
A point mass is placed inside a thin spherical shell of radius R and mass M at a distance R/2 from the centre of the shell. The gravitational force exerted by the shellon the point mass is

  • Physics-Gravitation-74873.png
  • 2)
    Physics-Gravitation-74874.png
  • Zero

  • Physics-Gravitation-74875.png
A particle of mass M is situated at the centre of a spherical shell of same mass and radius a. The magnitude of the gravitational potential at a point situated at a/2 distance from the centre, will be

  • Physics-Gravitation-74876.png
  • 2)
    Physics-Gravitation-74877.png

  • Physics-Gravitation-74878.png

  • Physics-Gravitation-74879.png
A particle of mass m is thrown upwards from the surface of the earth, with a velocity u. The mass and the radius of the earth are, respectively, M and R. G is gravitational constant and g is acceleration due to gravity on the surface of the earth. The minimum value of u so that the particle does not return back to earth, is

  • Physics-Gravitation-74881.png
  • 2)
    Physics-Gravitation-74882.png

  • Physics-Gravitation-74883.png

  • Physics-Gravitation-74884.png
The mass and radius of the sun are 1.99 × 1030 kg and R = 6.96 × 108 m. The escape velocity of a rocket from the Sun is
  • 11.2 km/s
  • 2.38 km/s
  • 59/5 km/s
  • 618 km/s
If ve and v0 represent the escape velocity and orbital velocity of a satellite corresponding to a circular orbitof radius R, then

  • Physics-Gravitation-74887.png
  • 2)
    Physics-Gravitation-74888.png

  • Physics-Gravitation-74889.png

  • Physics-Gravitation-74890.png
Geostationary satellite
  • Falls with g towards the earth
  • Has period of 24 hrs
  • Has equatorial orbit
  • Above all correct
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
  • Fall vertically down to the earth
  • Move towards the moon
  • Will move along with space-ship
  • Will move in an irregular way then fall down to earth
A synchronous satellite goes around the earth once in every 24 h. What is the radius of orbit of the synchronous satellite in terms of the earth\'s radius (Given mass of the earth, me = 5.98 × 1024 kg, radius of earth, re = 6.37 × 106m. Universal constant of gravitation, G = 6.67 × 10–11 Nm2–kg–2
  • 2.4re
  • 3.6re
  • 4.8re
  • 6.6re
Two satellites A and B go round a planet P in circular orbits having radii 4R and R respectively. If the speed of the satellite A is 3V, the speed of the satellite B will be
  • 12 V
  • 6 V
  • 4/3V
  • 3/2V
A small satellite is revolving near earth\'s surface. Itsorbital velocity will be nearly
  • 8 km/sec
  • 11.2 km/sec
  • 4 km/sec
  • 6 km/sec
If the height of a satellite from the earth is negligible in comparison to the radius of the earth R, the orbital velocity of the satellite is

  • Physics-Gravitation-74894.png
  • 2)
    Physics-Gravitation-74895.png

  • Physics-Gravitation-74896.png

  • Physics-Gravitation-74897.png
Orbital velocity of an artificial satellite does not depend upon
  • Mass of the earth
  • Mass of the satellite
  • Radius of the earth
  • Acceleration due to gravity
The satellite of mass m revolving in a circular orbit of radius r around the earth has kinetic energy E. Then its angular momentum will be

  • Physics-Gravitation-74899.png
  • 2)
    Physics-Gravitation-74900.png

  • Physics-Gravitation-74901.png

  • Physics-Gravitation-74902.png
Orbital velocity of earth\'s satellite near the surface is 7 km/s. When the radius of the orbit is 4 times than that of earth\'s radius, then orbital velocity in that orbit is
  • 3.5 km/s
  • 7 km/s
  • 72 km/s
  • 14 km/s
Two identical satellites are at R and 7R away from earth surface, the wrong statement is (R = Radius of earth)
  • Ratio of total energy will be 4
  • Ratio of kinetic energies will be 4
  • Ratio of potential energies will be 4
  • Ratio of total energy will be 4 but ratio of potential and kinetic energies will be 2
The mean radius of the earth is R, its angular speed on its own axis is ω and the acceleration due to gravity atearth\'s surface is g. The cube of the radius of the orbit of a geostationary satellite will be
  • R2g / ω
  • R2ω2 / g
  • Rg / ω2
  • R2g / ω2
Which one of the following statements regarding artificial satellite of the earth is incorrect?
  • The orbital velocity depends on the mass of the satellite
  • A minimum velocity of 8 km/sec is required by a satellite to orbit quite close to the earth
  • The period of revolution is large if the radius of its orbit is large
  • The height of a geostationary satellite is about 36000 km from earth
The weight of an astronaut, in an artificial satellite revolving around the earth, is
  • Zero
  • Equal to that on the earth
  • More than that on the earth
  • Less than that on the earth
The periodic time of a communication satellite is
  • 6 hours
  • 12 hours
  • 18 hours
  • 24 hours
The distance of a geo-stationary satellite from the centre of the earth (Radius R = 6400 km) is nearest to
  • 5R
  • 7 R
  • 10 R
  • 18 R
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]

  • Physics-Gravitation-74907.png
  • 2)
    Physics-Gravitation-74908.png

  • Physics-Gravitation-74909.png

  • Physics-Gravitation-74910.png
Given radius of earth \'R\' and length of a day \'T\' the height of a geostationary satellite is [G-Gravitational Constant, M-Mass of Earth]

  • Physics-Gravitation-74912.png
  • 2)
    Physics-Gravitation-74913.png

  • Physics-Gravitation-74914.png

  • Physics-Gravitation-74915.png
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
  • 10 hr
  • 2)
    Physics-Gravitation-74917.png
  • 6 hr

  • Physics-Gravitation-74918.png
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
  • 0.7
  • 1.0
  • 1.5
  • 3
Where can a geostationary satellite be installed?
  • Over any city on the equator
  • Over the north or south pole
  • At height R above earth
  • At the surface of earth
Two satellites of earth S1 and S2 are moving in the same orbit. The mass of S1is four times the mass of S2. Which one of the following statements is true?
  • The time period of S1 is four times that of S2
  • The potential energies of earth and satellite in the two cases are equal
  • S1 and S2 are moving with the same speed
  • The kinetic energies of the two satellites are equal
If the gravitational force between two objects were proportional to 1/R (and not as 1/R2) where R is separation between them, then a particle in circular orbit under such a force would have its orbital speed v proportional to
  • 1/R2
  • R0
  • R1
  • 1/R
A satellite moves around the earth in a circular orbit of radius r with speed v. If the mass of the satellite is M, its total energy is

  • Physics-Gravitation-74923.png
  • 2)
    Physics-Gravitation-74924.png

  • Physics-Gravitation-74925.png

  • Physics-Gravitation-74926.png
A satellite with kinetic energy Ek is revolving round the earth in a circular orbit. How much more kinetic energy should be given to it so that it may just escape into outerspace
  • Ek
  • 2 Ek
  • 1/2 Ek
  • 3 Ek
Potential energy of a satellite having mass \'m\' and rotating at a height of 6.4 × 106 m from the earth surface is
  • –0.5 mgRe
  • –mgRe
  • –2 mgRe
  • 4mgRe
When a satellite going round the earth in a circular orbit of radius r and speed v loses some of its energy, then r and v change as
  • r and v both will increase
  • r and v both will decrease
  • r will decrease and v will increase
  • r will decrease and v will decrease
If satellite is shifted towards the earth. Then time period of satellite will be
  • Increase
  • Decrease
  • Unchanged
  • Nothing can be said
Two satellites A and B go round a planet in circular orbits having radii 4R and R, respectively. If the speed of satellite A is 3v, then speed of satellite B is

  • Physics-Gravitation-74932.png
  • 2)
    Physics-Gravitation-74933.png

  • Physics-Gravitation-74934.png

  • Physics-Gravitation-74935.png

Physics-Gravitation-74937.png

  • Physics-Gravitation-74938.png
  • 2)
    Physics-Gravitation-74939.png

  • Physics-Gravitation-74940.png

  • Physics-Gravitation-74941.png
A satellite moves in a circle around the earth. The radius of this circle is equal to one half of the radius of the moon\'s orbit. The satellite completes one revolution in
  • 1/2 lunar month
  • 2/3 lunar month
  • 2–3/2 lunar month
  • 23/2 lunar month
0:0:1


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