CBSE Class 11 Physics Gravitation Worksheet

Question-  In a gravitational field, at a point where the gravitational potential is zero

(a) the gravitational field is necessarily zero

(b) the gravitational field is not necesarily zero

(c) any value between one and infinite

(d) None of these

Answer-(a)

Question-The value of G varies with

(a) height above the earth's surface

(b) depth below the ground

(c) radius of the planet

(d) None of these

Answer-(d)

Question-In some region, the gravitational field is zero. The gravitational potential in this region.

(a) must be variable

(b) must be constant

(c) cannot be zero

(d) must be zero

Answer-(b)

Question-Force of gravitational attraction is least

(a) at the equator

(b) at the poles

(c) at a point in between equator and any pole

(d) None of these

Answer-(a)

Question-Earth is flattened at poles, bulged at the equator. This is due to

(a) the angular velocity of spinning about its axis is less at equator

(b) the angular velocity of spinning about its axis is more at equator

(c) the centrifugal force is more at the equator than at the poles

(d) earth revolves round the sun in an elliptical orbit

Answer-(c)

Question- Who among the following gave first the experimental value of G

(a) Cavendish

(b) Copernicus

(c) Brok Taylor

(d) None of these

Answer-(a)

Question-Where will it be profitable to purchase one kilogram sugar?

(a) At poles

(b) At equator

(c) At 45° latitude

(d) At 40° latitude

Answer-(a)

Question-Mass of the Earth has been determined through

(a) use of Kepler's T²/R³ constancy law and Moon's period

(b) sampling the density of Earth's crust and using Earth's radius

(c) Cavendish's determination of G and using Earth radius and g at its surface

(d) use of periods of satellites at different heights above Earth's surface and known radius of Earth

Answer-(c)

Question-Newton's universal law of gravitation applies to

(a) small bodies only

(b) planets only

(c) both small and big bodies

(d) only valid for solar system

Answer-(c)

Question-Consider Earth to be a homogeneous sphere. Scientist A goes deep down in a mine and scientist B goes high up in a balloon. The gravitational field measured by

(a) A goes on decreasing and that by B goes on increasing

(b) B goes on decreasing and that by A goes on increasing

(c) each decreases at the same rate

(d) each decreases at different rates

Answer-(d)

Question- At sea level, a body will have minimum weight at

(a) pole

(b) equator

(c) 42° south latitude

(d) 37° north latitude

Answer-(b)

Question-The ratio of the inertial mass to gravitational mass is equal to

(a) 0.5

(b) 1

(c) 2

(d) no fixed number

Answer-(c)

Question- There are _______ gravitational lines of force inside a spherically symmetric shell.

(a) infinitely many

(b) zero

(c) varying number depending upon surface area

(d) varying number depending upon volume

Answer-(b)

Question- Two spheres of masses m and 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) 3 F

(b) F

(c) F/3

(d) F/9

Answer-(b)

Question- Intensity of the gravitational field inside the solid sphere is

(a) variable (proportional to distance from centre)

(b) constant

(c) variable (does not depend on distance from the centre)

(d) zero

Answer-(a)

Question-Kepler’s second law regarding constancy of areal velocity of a planet is a consequence of the law of conservation of

(a) energy

(b) angular momentum

(c) linear momentum

(d) None of these

Answer-(b)

Question-The value of acceleration due to gravity on moving from equator to poles will

(a) decrease

(b) increase

(c) remain same

(d) become half

Answer-(b)

Question-If the earth is at one-fourth of its present distance from the sun, the duration of the year will be

(a) half the present year

(b) one-eighth the present year

(c) one-sixth the present year

(d) one-tenth the present year

Answer-(b)

Question- As we go down below the earth's surface, the acceleration due to gravity decreases by a factor (d → distance, R → radius of earth)

(a) 1 +d/R

(b) 1- R/d

(c) 1- d/R

(d) remains constant

Answer-(c)

Question-Intensity of the gravitational field inside the hollow spherical shell is

(a) variable

(b) minimum

(c) maximum

(d) zero

Answer-(d)

Question-If measured by a spring balance, then 1 kg of salt will weigh more at

(a) equator

(b) poles

(c) centre of earth

(d) same at all places

Answer-(b)

Question-In planetary motion

(a) the angular speed remains constant

(b) the total angular momentum remains constant

(c) the linear speed remains constant

(d) neither the angular momentum nor angular speed remains constant

Answer-(b)

Question- In planetary motion, the angular momentum conservation leads to the law of

(a) orbits

(b) areas

(c) periods

(d) conservation of kinetic energy

Answer-(b)

Question- In motion of an object under the influence of gravitational force of another object, which of the following quantity is not conserved?

(a) Linear momentum

(b) Angular momentum

(c) Total mechanical energy

(d) None of these

Answer-(a)

Question-Weightlessness experienced while orbiting the earth in spaceship is the result of

(a) inertia

(b) acceleration

(c) zero gravity

(d) centre of gravity

Answer-(c)

Question-If the distance of earth is halved from the sun, then the no. of days in a year will be

(a) 365

(b) 182.5

(c) 730

(d) 129

Answer-(d)

Question- Time period of a simple pendulum inside a satellite orbitin earth is

(a) zero

(b)∞

(c) T

(d) 2 T

Answer-(b)

Question-There is no atmosphere on moon, because of

(a) smaller value of G

(b) smaller value of g

(c) smaller value of R

(d) smaller value of m

Answer-(b)

Question-The weight of a body at the centre of the earth is

(a) zero

(b) infinite

(c) same as on the surface of earth

(d) None of these

Answer-(a)

Question- Persons sitting in artificial satellite of the earth have

(a) zero mass

(b) zero weight

(c) certain definite weight

(d) infinite weight

Answer-(b)

Question-The escape velocity of a body depends upon mass as

(a) m⁰

(b) m¹

(c) m²

(d) m³.

Answer-(a)

Question-The orbit traced by planet around a star is in general

(a) a circle

(b) an ellipse

(c) a parabola

(d) a straight line

Answer-(b)

Question-Which of the following is always positive?

(a) Potential energy of an object

(b) Total energy of a satellite

(c) Kinetic energy

(d) None of these

Answer-(c)

Question-The minimum velocity of projection to go out from the earth’s gravitational pull is called

(a) terminal velocity

(b) escape velocity

(c) angular velocity

(d) orbital velocity

Answer-(b)

Question-What is the distance of a geostationary satellite from the earth's centre?

(a) 4.22 × 10⁴ km

(b) 4.22 × 10⁴ m

(c) 4.22 × 10⁶ km

(d) 4.22 × 10⁶ m

Answer-(a)

Question-There is no atmosphere on the moon because

(a) it is closer to the earth

(b) it revolves round the earth

(c) it gets light from the sun

(d) the escape velocity of gas molecules is lesser than their root mean square velocity

Answer-(d) 

Question-When does the object in a satellite escapes to infinity?

(a) When the total energy is positive

(b) When total energy is zero

(c) Both (a) & (b)

(d) None of these

Answer-(c)

Question-The escape velocity of an object projected from the surface of a given planet is independent of

(a) radius of the planet

(b) the direction of projection

(c) the mass of the planet

(d) None of these

Answer-(b)

Question-The period of a satellite in a circular orbit near a planet is independent of

(a) the mass of the planet

(b) the radius of the planet

(c) the mass of the satellite

(d) All of the above

Answer-(c)

Question-The escape velocity of a projectile from the earth is approximately

(a) 7 km/sec

(b) 112 km/sec

(c) 11.2 km/sec

(d) 1.1 km/sec

Answer-(c)

Question-If a satellite is orbiting the earth very close to its surface, then the orbital velocity mainly depends on

(a) the mass of the satellite

(b) the radius of earth

(c) the orbital radius

(d) the mass of earth

Answer-(b)

Question-In which of the following cases, a person feels weightless?

(a) A person standing on the moon

(b) A person sitting in an artificial satellite of earth

(c) Both (a) & (b)

(d) None of these

Answer-(b)

Question-In case of a circular orbiting satellite which option is correct for its energies?

(a) Kinetic energy is negative

(b) Potential energy is positive

(c) Total energy is positive

(d) None of these

Answer-(d)

Question-A person sitting in a chair in a satellite feels weightless because

(a) the earth does not attract the objects in a satellite

(b) the normal force bythe chair on the person balances the earth's attraction

(c) the normal force is zero

(d) the person in satellite is not accelerated.

Answer-(c)

Question- Two satellites of masses m₁ and m₂ (m₁ > m₂) are revolving round the earth in circular orbits of radii r₁ and r2 (r₁ > r₂) respectively. Which of the following statements is true regarding their velocities v₁ and v₂?

(a) v₁ = v₂

(b) v₁ < v₂

(c) v₁ > v₂

(d) (v₁ / r₂) = (v₂ / r₂)

Answer-(b)

Question-Escape speed on the moon is _______ than escape speed on the earth.

(a) five times smaller

(b) five times greater

(c) six times greater

(d) six times smaller

Answer-(a)

Question. A man waves his arms while walking. This is to
(a) keep constant velocity
(b) ease the tension
(c) increase the velocity
(d) balance the effect of earth’s gravity

Answer: D

Question. Due to rotation of the earth the acceleration due to gravity g is
(a) maximum at the equator and minimum at the poles
(b) minimum at the equator and maximum at the poles
(c) same at both places
(d) None of these

Answer: B

Question. A planet moves around the sun. At a point P it is closest from the sun at a distance d₁ and has a speed v₁. At another point Q, when it is farthest from the sun at a distance d₂ its speed will be
(a) d₁²v₁/d₂²
(b) d₂ v₁ / d₁
(c) d₁ v₁ / d₂
(d) d₂²v₁/d₁²

Answer: C

Question. The weight of an object in the coal mine, sea level and at the top of the mountain, are respectively W₁, W₂ and W₃ then
(a) W₁< W₂ > W₃
(b) W₁= W₂ = W₃
(c) W₁< W₂ < W₃
(d) W₁> W₂ > W₃

Answer: A

Question. Two planets of radii r₁ and r₂ are made from the same material. The ratio of the acceleration due to gravity g₁/g₂ at the surfaces of the two planets is
(a) r₁/r₂
(b) r₂/r₁
(c) (r₁/r₂)²
(d) (r₂/r₁)²

Answer: A

Question. What would be the length of a sec. pendulum at a planet (where acc. due to gravity is g/4) if it’s length on earth is l
(a) l/2
(b) 2 l
(c) l/4
(d) 4 l

Answer: C

Question. The radii of circular orbits of two satellites A and B of the earth, are 4R and R, respectively. If the speed of satellite A is 3 V, then the speed of satellite B will be
(a) 3 V/4
(b) 6 V
(c) 12 V
(d) 3 V/2

Answer: B

Question. Energy required to move a body of mass m from an orbit of radius 2R to 3R is
(a) GMm/12R²
(b) GMm/3R²
(c) GMm/8R
(d) GMm/6R

Answer: D

Question. The escape velocity from the earth's surface is 11 km/s. The escape velocity from a planet having twice the radius and same mean density as that of earth is
(a) 5.5 km/s
(b) 11 km/s
(c) 22 km/s
(d) None of these

Answer: C

Question. Time period of a simple pendulum inside a satellite orbiting earth is
(a) zero
(b) ∞
(c) T
(d) 2 T

Answer: B

Question. The kinetic energy needed to project a body of mass m from the earth surface (radius R) to infinity is
(a) mgR/2
(b) 2mgR
(c) mgR
(d) mgR/4.

Answer: C

Question. The escape velocity of a body depends upon mass as
(a) m⁰
(b) m¹
(c) m²
(d) m³

Answer: A

Question. The gravitational force of attraction between a uniform sphere of mass M and a uniform rod of length l and mass m oriented as shown is 

(a) GMm/r(r + l)
(b) GM/r²
(c) Mmr² + l
(d) (r² + l)mM

Answer: A

Question. Two satellites revolve round the earth with orbital radii 4R and 16R, if the time period of first satellite is T then that of the other is
(a) 4 T
(b) 42/3 T
(c) 8 T
(d) None of these

Answer: C

Question. Which of the following quantities do not depend upon the orbital radius of the satellite ?
(a) T/R
(b) T²/R
(b) T²/R²
(d) T²/R³

Answer: D

Question. A satellite of mass ‘m’, moving around the earth in a circular orbit of radius R, has angular momentum L. The areal velocity of satellite is (M_e = mass of earth)
(a) L /2m
(b) L /m
(c) 2L /m
(d) 2L /Me

Answer: A

Question. A planet revolves in an elliptical orbit around the sun. The semi-major and semi-minor axes are a and b. Then the square of time period, T is directly proportional to
(a) a³
(b) b³
(c) (a+b/2)³
(d) (a-b/2)³

Answer: A

Question. The radius of a planet is 1/4th of Re and its acc. due to gravity is 2g. What would be the value of escape velocity on the planet, if escape velocity on earth is ve.
(a) v_e/√2
(b) v_e√2
(c) 2 v_e
(d) v_e/2

Answer: A

Question. If the gravitational force had varied as r^–5/2 instead of r^–2; the potential energy of a particle at a distance ‘r’ from the centre of the earth would be proportional to
(a) r^-1
(b) r^-2
(c) r^{-3 / 2}
(d) r^-5 / 2

Answer: C

Question. A solid sphere of uniform density and radius R applies a gravitational force of attraction equal to F₁ on a particle placed at A, distance 2R from the centre of the sphere.
A spherical cavity of radius R/2 is now made in the sphere as shown in the figure. The sphere with cavity now applies a gravitational force F2 on the same particle placed at A. The ratio F₂/F₁ will be
(a) 1/2
(b) 3
(c) 7
(d) 1/9

Answer: D

Question. The earth is assumed to be sphere of radius R. A platform is arranged at a height R from the surface of Earth. The escape velocity of a body from this platform is kv, where v is its escape velocity from the surface of the earth. The value of k is
(a) 1/√2
(b) 1/3
(c) 1/2
(d) √2 

Answer: A

Question. The escape velocity for a body projected vertically upwards from the surface of earth is 11 km/s. If the body is projected at an angle of 45º with the vertical, the escape velocity will be
(a) 22 km/s
(b) 11 km/s
(c) 11/√2 km/s
(d) 11 √2 km/s

Answer: B

Question. Explorer 38, a radio-astronomy satellite of mass 200 kg, circles the Earth in an orbit of average radius 3R/2 where R is the radius of the Earth. Assuming the gravitational pull on a mass of 1 kg at the earth's surface to be 10 N, calculate the pull on the satellite
(a) 889 N
(b) 89 N
(c) 8889 N
(d) 8.9 N

Answer: A

Question. The orbital velocity of an artificial satellite in a circular orbit very close to Earth is v. The velocity of a geosynchronous satellite orbiting in a circular orbit at an altitude of 6R from Earth's surface will be
(a) v/√7
(b) v/√6
(c) v
(d) √6v

Answer: A

Question. Escape velocity when a body of mass m is thrown vertically from the surface of the earth is v, what will be the escape velocity of another body of mass 4 m is thrown vertically
(a) v
(b) 2v
(c) 4v
(d) None of these

Answer: A

Question. The potential energy of a satellite of mass m and revolving at a height Re above the surface of earth where R_e = radius of earth, is
(a) – m g R_e
(b) -mg R_e/2
(c) -mg R_e/3
(d) -mg Re/4

Answer: B

Question. 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 = 1 km
(b) d = 3/2km
(c) d = 2 km
(d) d = 1/2km

Answer: C

Question. If the mass of earth is eighty times the mass of a planet and diameter of the planet is one fourth that of earth, then acceleration due to gravity on the planet would be
(a) 7.8 m/s²
(b) 9.8 m/s²
(c) 6.8 m/s²
(d) 2.0 m/s²

Answer: D

Question. A satellite is orbiting around the earth near its surface. If its kinetic energy is doubled, then
(a) it will remain in the same orbit.
(b) it will fall on the earth.
(c) it will revolve with greater speed.
(d) it will escape out of the gravitational field of the earth.

Answer: D

Question. The ratio of the radii of the planets R₁ and R₂ is k. The ratio of the acceleration due to gravity is r. The ratio of the escape velocities from them will be
(a) k r
(b) √kr
(c) √(k / r)
(d) √(r / k)

Answer: B

Question. The distance of neptune and saturn from the sun is nearly 10¹³ and 10¹² meter respectively. Assuming that they move in circular orbits, their periodic times will be in the ratio
(a) 10
(b) 100
(c) 10 √10
(d) 1000

Answer: C

Question. A geostationary satellite is orbiting the earth at a height of 5R above that surface of the earth, R being the radius of the earth. The time period of another satellite in hours at a height of 2R from the surface of the earth is
(a) 5
(b) 10
(c) 6√2
(d) 6/√2

Answer: C

Question. A (nonrotating) star collapses onto itself from an initial radius R_i with its mass remaining unchanged. Which curve in figure best gives the gravitational acceleration a_g on the surface of the star as a function of the radius of the star during the collapse 

(a) a
(b) b
(c) c
(d) d

Answer: B

Question. If the length of a simple pendulum is increased by 2%, then the time period
(a) increases by 2%
(b) decreases by 2%
(c) increases by 1%
(d) decreases by 1%

Answer: C

Question. The density of a newly discovered planet is twice that of earth. The acceleration due to gravity at the surface of the planet is equal to that at the surface of the earth. If the radius of the earth is R, the radius of the planet would be
(a) ^½ R
(b) 2 R
(c) 4 R
(d) 1/4 R

Answer: A

Question. The kinetic energy of a satellite in its orbit around the earth is E. What should be the kinetic energy of the satellite so as to enable it to escape from the gravitational pull of the earth?
(a) 4 E
(b) 2 E
(c) √2 E
(d) E

Answer: B

Question. The time period of a satellite in a circular orbit of radius R is T, the period of another satellite in a circular orbit of radius 4 R is
(a) 4 T
(b) T/4
(c) 8 T
(d) T/8

Answer: C

Question. If the change in the value of g at the height h above the surface of the earth is the same as at a depth ‘x’ below it, then (both x and h being much smaller than the radius of the earth)
(a) x = h
(b) x = 2 h
(c) x = h/2
(d) x = h²

Answer: B

Question. A satellite of mass m revolves around the earth of radius R at a height ‘x’ from its surface. If g is the acceleration due to gravity on the surface of the earth, the orbital speed of the satellite is
(a) gR²/R + x
(b) gR/R - x
(c) gx
(d) (gR²/R + x)^1/2

Answer: D

Question. The time period of an earth satellite in circular orbit is independent of
(a) both the mass and radius of the orbit
(b) radius of its orbit
(c) the mass of the satellite
(d) neither the mass of the satellite nor the radius of its orbit.

Answer: C

Question. Suppose the gravitational force varies inversely as the nth power of distance. Then the time period of a planet in circular orbit of radius ‘R’ around the sun will be proportional to
(a) Rn
(b) R ^(n-1/2)
(c) R^(n+1/2)
(d) R ^(n-2/2)

Answer: C

Question. There is no atmosphere on the moon because
(a) it is closer to the earth and also it has the inactive inert gases in it.
(b) it is too for from the sun and has very low pressure in its outer surface.
(c) escape velocity of gas molecules is greater than their root mean square velocity.
(d) escape velocity of gas molecules is less than their root mean square velocity.

Answer: D

Question. The maximum kinetic energy of a planet moving around the sun is at a position

(a) A
(b) B
(c) C
(d) D

Answer: A

Question. Consider Earth to be a homogeneous sphere. Scientist A goes deep down in a mine and scientist B goes high up in a balloon. The gravitational field measured by
(a) A goes on decreasing and that by B goes on increasing
(b) B goes on decreasing and that by A goes on increasing
(c) each decreases at the same rate
(d) each decreases at different rates

Answer: D

Question. Two point masses each equal to 1 kg attract one another with a force of 10^–10 N. The distance between the two point masses is (G = 6.6 × 10^–11 MKS units)
(a) 8 cm
(b) 0.8 cm
(c) 80 cm
(d) 0.08 cm

Answer: C

Question. Two astronauts are floating in gravitation free space after having lost contact with their spaceship. The two will
(a) move towards each other.
(b) move away from each other.
(c) become stationary
(d) keep floating at the same distance between them.

Answer: A

Question. If there were a small gravitational effect, then which of the following forces will undergo a change?
(a) Viscous force
(b) Electrostatic force
(c) Magnetic force
(d) Archimedes' uplift

Answer: D

Question. The ratio of the kinetic energy required to be given to a satellite so that it escapes the gravitational field of Earth to the kinetic energy required to put the satellite in a circular orbit just above the free surface of Earth is
(a) 1
(b) 2
(c) 3
(d) 9

Answer: B

Question. The radii of two planets are respectively R₁ and R₂ and their densities are respectively r₁ and r₂. The ratio of the accelerations due to gravity at their surfaces is
(a) g₁:g₂ = ρ₁/R₁² : ρ₂/R₂²
(b) g₁ : g₂ = R₁R₂ : ρ₁ρ₂
(c) g₁ : g₂ = R₁r₂ : R₂ρ₁
(d) g₁ : g₂ = R₁ρ₁ : R₂ρ₂

Answer: D

Question. An artificial satellite moving in a circular orbit around the earth has a total (K.E. + P.E.) is E₀. Its potential energy is –
(a) –E₀
(b) 1.5 E₀
(c) 2E₀
(d) E₀

Answer: C