Universal law of gravitation and gravitational potential - Question Bank

1. The gravitational force between two point masses is attractive and acts along the line joining their centers. This statement is a part of:
A) Kepler's Laws
B) Newton's Universal Law of Gravitation
C) Newton's Laws of Motion
D) Law of Conservation of Momentum
2. The gravitational potential at a point is zero if:
A) The point is at infinity
B) The source mass is zero
C) The point is at the center of a uniform ring
D) All of the above
3. What is the gravitational potential energy of a system of three masses m, 2m, and 3m placed at the vertices of an equilateral triangle of side a?
A) -G(11m²)/(2a)
B) -G(5m²)/a
C) -G(11m²)/a
D) -G(5m²)/(2a)
4. The gravitational force between two point masses is given by F = G(m₁m₂)/r². If the masses are doubled and the distance is also doubled, the new force will be:
A) F/4
B) F/2
C) F
D) 2F
5. If the distance between two masses M and m is increased from r to 2r, the gravitational potential energy changes by a factor of:
A) 1/2
B) 2
C) 1/4
D) 4
6. The gravitational potential at a point is the work done by an external agent against the gravitational field to bring a unit mass from infinity to that point.
A) True, and the potential is positive
B) True, and the potential is negative
C) False, it is work done by the field
D) False, it is energy per unit volume
7. The gravitational force between two bodies is dependent on:
A) Their masses and the distance between their centers
B) Their masses and the distance between their surfaces
C) Their volumes and the distance between their centers
D) Their densities and the distance between their centers
8. The gravitational potential energy of a system of two identical masses m separated by a distance r is:
A) Gm²/r
B) -Gm²/r
C) 2Gm²/r
D) -2Gm²/r
9. If the Earth's mass is doubled and its radius is halved, the acceleration due to gravity on its surface would become:
A) Half
B) Same
C) Twice
D) Four times
10. The gravitational force between two point masses is independent of the nature of the medium separating them. This property is similar to:
A) Electric force
B) Magnetic force
C) Nuclear force
D) Friction force
11. Which of the following statements is correct regarding gravitational potential?
A) It is a vector quantity.
B) It is always positive for any mass.
C) It represents the potential energy per unit mass.
D) Its value is zero at infinity and positive everywhere else.
12. If the mass of the Earth is M and its radius is R, the gravitational potential energy of a mass m at its surface is approximately:
A) mgR
B) -mgR
C) GMm/R²
D) -GMm/R²
13. The gravitational field strength due to a point mass M at a distance r is given by:
A) GM/r
B) -GM/r
C) GM/r²
D) -GM/r²
14. The work done by gravity when a mass moves from infinity to a point at distance r from a mass M is:
A) GMm/r
B) -GMm/r
C) GMm/r²
D) -GMm/r²
15. If two masses are moved farther apart, their gravitational potential energy:
A) Increases
B) Decreases
C) Remains constant
D) Becomes zero
16. What is the gravitational potential at the center of a uniform solid sphere of mass M and radius R?
A) -3GM/(2R)
B) -GM/R
C) -GM/(2R)
D) Zero
17. The gravitational force between two point masses is proportional to:
A) The square of the distance between them
B) The inverse square of the distance between them
C) The distance between them
D) The inverse of the distance between them
18. If the radius of the Earth is R, the gravitational potential energy of a mass m at a height h above the surface is:
A) -GMm/(R+h)
B) GMm/(R+h)
C) -GMm/h
D) GMm/h
19. The gravitational potential energy of a system of two particles is zero when:
A) They are at the same position
B) They are infinitely far apart
C) They are at the center of the universe
D) Their masses are equal
20. The gravitational field strength at a point is defined as the gravitational force per unit:
A) Mass
B) Charge
C) Volume
D) Area
21. If the mass of the Earth becomes twice its present value, what would be the gravitational potential energy of a satellite of mass m in the same orbit?
A) It remains the same
B) It becomes half
C) It becomes double
D) It becomes four times
22. The gravitational force between two masses is a conservative force. This implies that:
A) Work done by it depends on the path
B) Work done by it in a closed path is zero
C) It cannot be derived from a potential energy function
D) It is always attractive
23. If the distance between two point masses is halved, the gravitational potential energy between them:
A) Is halved
B) Is doubled
C) Becomes one-fourth
D) Becomes four times
24. What is the gravitational potential at the surface of the Earth (radius R, mass M)?
A) GM/R
B) -GM/R
C) GM/R²
D) -GM/R²
25. The gravitational potential energy of a system of n particles is the sum of the potential energies of all possible pairs of particles.
A) True
B) False
C) Depends on the arrangement
D) Only true for two particles
26. If the Earth suddenly stops rotating, the weight of a person standing on the equator will:
A) Increase
B) Decrease
C) Remain the same
D) Become zero
27. The gravitational force between two point masses is proportional to the inverse square of the distance between them. This is known as the:
A) Inverse square law
B) Newton's Law of Cooling
C) Coulomb's Law
D) Hooke's Law
28. Gravitational potential is a measure of potential energy per unit:
A) Mass
B) Volume
C) Area
D) Force
29. If the radius of the Earth were to decrease by 1%, what would be the approximate change in the acceleration due to gravity on its surface, assuming mass remains constant?
A) 1% increase
B) 1% decrease
C) 2% increase
D) 2% decrease
30. The gravitational potential inside a uniform solid sphere of mass M and radius R at a distance r from the center (r < R) is given by:
A) -GM(3R² - r²)/(2R³)
B) -GM(3R² + r²)/(2R³)
C) -GM(R² - r²)/(2R³)
D) -GM(2R² - r²)/(2R³)
31. The value of the gravitational constant G was first measured experimentally by:
A) Isaac Newton
B) Henry Cavendish
C) Albert Einstein
D) Michael Faraday
32. If a body of mass m is at a distance r from the center of the Earth (mass M), its gravitational potential energy is -GMm/r. If the body moves to a distance 2r, its potential energy will become:
A) -GMm/(4r)
B) -GMm/(2r)
C) -GMm/(8r)
D) -GMm/(16r)
33. The gravitational force exerted by the Earth on the Moon is equal in magnitude to the gravitational force exerted by the Moon on the Earth. This is an application of:
A) Newton's First Law
B) Newton's Second Law
C) Newton's Third Law
D) Law of Conservation of Energy
34. What is the gravitational potential energy of a mass 'm' at a distance 'r' from a mass 'M'?
A) GMm/r
B) -GMm/r
C) GMm/r²
D) -GMm/r²
35. The gravitational field strength at a point is equal to the negative gradient of the gravitational potential.
A) True
B) False
C) Depends on the mass
D) Depends on the distance
36. The gravitational potential at the center of a uniform spherical shell of mass M and radius R is:
A) -GM/R
B) Zero
C) -GM/(2R)
D) -2GM/R
37. The gravitational force between two point masses m1 and m2 separated by a distance r is F. If the distance is reduced to r/2, the new force will be:
A) F/4
B) F/2
C) 2F
D) 4F
38. If we move from the surface of the Earth towards its center, the gravitational potential:
A) Increases
B) Decreases
C) Remains constant
D) First increases then decreases
39. The gravitational potential energy of a system of two masses is defined as the work done by an external agent against the gravitational force to separate the masses to an infinite distance. What is its sign?
A) Positive
B) Negative
C) Zero
D) Can be positive or negative
40. Gravitational potential is a:
A) Scalar quantity
B) Vector quantity
C) Tensor quantity
D) Complex quantity
41. What is the dimension of the gravitational constant G?
A) [M⁻¹L³T⁻²]
B) [M¹L³T⁻²]
C) [M⁻¹L³T⁻¹]
D) [M¹L³T⁻³]
42. The gravitational force between two masses is independent of:
A) The masses of the bodies
B) The distance between the bodies
C) The medium between the bodies
D) The gravitational constant
43. If the mass of one of the bodies is doubled, while the distance remains the same, the gravitational force between them:
A) Remains the same
B) Becomes half
C) Becomes double
D) Becomes four times
44. The gravitational potential due to a point mass 'M' at a distance 'r' is given by:
A) GM/r
B) -GM/r
C) GM/r²
D) -GM/r²
45. What is the gravitational potential at infinity?
A) Infinity
B) -Infinity
C) Zero
D) Undefined
46. Gravitational potential at a point is defined as the work done in bringing a unit mass from infinity to that point. What is the sign of gravitational potential?
A) Positive
B) Negative
C) Zero
D) Can be positive or negative
47. The universal law of gravitation was formulated by:
A) Galileo Galilei
B) Isaac Newton
C) Albert Einstein
D) Johannes Kepler
48. If the distance between two point masses is doubled, the gravitational force between them becomes:
A) Double
B) Half
C) One-fourth
D) Four times
49. The gravitational force between two bodies is:
A) Always attractive
B) Always repulsive
C) Can be attractive or repulsive
D) Zero
50. According to Newton's universal law of gravitation, the force of attraction between two point masses is directly proportional to:
A) The sum of their masses
B) The difference of their masses
C) The product of their masses
D) The square of the sum of their masses