Q.1 The universal gravitational constant (G) has the unit of:
N·m²/kg²
kg·m/s²
m/s²
N/kg
Explanation - The gravitational force formula is F = G * (m1 * m2) / r². Rearranging for G gives units of N·m²/kg².
Correct answer is: N·m²/kg²
Q.2 If the mass of the Earth doubles and the distance from its center remains the same, the gravitational force on a body will:
Halve
Double
Remain unchanged
Become four times
Explanation - Gravitational force is directly proportional to the product of masses. Doubling Earth's mass doubles the force.
Correct answer is: Double
Q.3 The value of G was first measured by:
Isaac Newton
Cavendish
Kepler
Einstein
Explanation - Henry Cavendish first measured the gravitational constant using a torsion balance in 1798.
Correct answer is: Cavendish
Q.4 The acceleration due to gravity decreases with:
Altitude
Depth
Both altitude and depth
Latitude only
Explanation - As altitude increases or depth increases, the distance from the Earth's center increases, reducing gravity.
Correct answer is: Both altitude and depth
Q.5 At what point between Earth and Moon is the net gravitational force on a body zero?
Closer to Earth
Exactly midway
Closer to Moon
It can be anywhere
Explanation - Since Earth has greater mass, the neutral point is closer to the Moon where Earth's pull balances Moon's pull.
Correct answer is: Closer to Moon
Q.6 Which of the following quantities remains constant throughout Earth?
Gravitational potential
Acceleration due to gravity
Gravitational constant G
Weight of a body
Explanation - G is a universal constant and does not change with location or condition.
Correct answer is: Gravitational constant G
Q.7 Gravitational potential energy is:
Always positive
Always negative
Zero at infinity
Both B and C
Explanation - Gravitational potential energy is negative because the force is attractive and zero at infinity by convention.
Correct answer is: Both B and C
Q.8 Kepler’s third law states that:
The square of time period is proportional to cube of radius
The square of time period is proportional to square of radius
The time period is inversely proportional to radius
The cube of time period is proportional to square of radius
Explanation - Kepler’s third law is T² ∝ r³ for planetary motion around the sun.
Correct answer is: The square of time period is proportional to cube of radius
Q.9 Escape velocity on Earth is approximately:
11.2 km/s
7.9 km/s
15.5 km/s
9.8 km/s
Explanation - Escape velocity for Earth is calculated as √(2gR), approximately 11.2 km/s.
Correct answer is: 11.2 km/s
Q.10 Weightlessness experienced in a satellite is due to:
Absence of gravity
Reduced mass of body
Free fall of satellite and body
Zero atmospheric pressure
Explanation - Both the satellite and the objects inside are in continuous free fall, creating a feeling of weightlessness.
Correct answer is: Free fall of satellite and body
Q.11 The value of acceleration due to gravity at the center of the Earth is:
Zero
Maximum
Equal to g
Half of g
Explanation - At the center of Earth, the net gravitational force is zero because all forces cancel each other out.
Correct answer is: Zero
Q.12 Which planet has the strongest surface gravity?
Earth
Jupiter
Mars
Venus
Explanation - Jupiter is the most massive planet, giving it the highest surface gravity.
Correct answer is: Jupiter
Q.13 The gravitational field at a point is defined as:
Force per unit area
Force per unit mass
Mass per unit force
Energy per unit volume
Explanation - Gravitational field is the force experienced by a unit mass at that point.
Correct answer is: Force per unit mass
Q.14 The orbital speed of a satellite depends on:
Its mass only
The mass of the planet and the radius of orbit
The shape of the satellite
The temperature of the atmosphere
Explanation - Orbital speed is √(GM/R), where M is the planet's mass and R is the orbital radius.
Correct answer is: The mass of the planet and the radius of orbit
Q.15 The acceleration due to gravity is maximum at:
Poles
Equator
Center of Earth
Everywhere equal
Explanation - Due to Earth's rotation and shape, gravity is slightly higher at poles.
Correct answer is: Poles
Q.16 The total energy of a body in a stable circular orbit is:
Positive
Negative
Zero
Depends on velocity
Explanation - For bound systems like orbits, total energy is negative because potential energy dominates over kinetic energy.
Correct answer is: Negative
Q.17 If the distance between two masses is tripled, the gravitational force becomes:
1/9 of original
1/3 of original
3 times original
9 times original
Explanation - According to the inverse square law, F ∝ 1/r². Tripling distance makes force 1/9th.
Correct answer is: 1/9 of original
Q.18 The satellite with least time period orbits:
At the greatest distance from Earth
At the least distance from Earth
At any distance
At geostationary orbit only
Explanation - Closer satellites have higher speed and complete an orbit faster according to Kepler's laws.
Correct answer is: At the least distance from Earth
Q.19 The force of gravity between two objects does not depend on:
Mass of objects
Distance between them
Value of G
Temperature of objects
Explanation - Gravity depends on mass and distance, not on temperature.
Correct answer is: Temperature of objects
Q.20 Which type of orbit is used for weather satellites?
Geostationary orbit
Polar orbit
Elliptical orbit
Equatorial orbit
Explanation - Weather satellites need to stay fixed relative to a point on Earth, requiring geostationary orbits.
Correct answer is: Geostationary orbit
Q.21 The weight of a body becomes zero at:
Equator
Poles
Free fall
Center of gravity of Earth
Explanation - In free fall, no normal reaction acts on the body, so weight appears to be zero.
Correct answer is: Free fall
Q.22 Kepler's laws are applicable to:
Artificial satellites only
Planets only
Both natural and artificial satellites
Only Sun and planets
Explanation - Kepler's laws apply to any object in orbit under gravity, natural or artificial.
Correct answer is: Both natural and artificial satellites
Q.23 A body weighs 100 N on Earth. On the Moon, it would weigh about:
100 N
60 N
16.5 N
600 N
Explanation - Gravity on the Moon is about 1/6th of Earth's gravity, so weight becomes 1/6th of 100 N.
Correct answer is: 16.5 N
Q.24 The gravitational potential at infinity is taken as:
Zero
Maximum
Negative
Positive
Explanation - By convention, gravitational potential is zero at infinity because there is no interaction at infinite separation.
Correct answer is: Zero