Gravitation Important Questions for NEET Physics - 2026

1. Multiple choice questions.

Q1. The gravitational force between two masses $m_1$ and $m_2$ separated by a distance $r$ is:

• (a) Directly proportional to $r$
• (b) Inversely proportional to $r^2$
• (c) Directly proportional to $r^2$
• (d) Inversely proportional to $r$

Answer: (b) Inversely proportional to $r^2$.

Q2. If the radius of earth shrinks by 1% and its mass remains unchanged, the acceleration due to gravity on the surface:

• (a) Increases by 2%
• (b) Decreases by 2%
• (c) Increases by 1%
• (d) Decreases by 1%

Answer: (a) Increases by 2%.

Q3. The escape velocity on Earth’s surface is approximately:

• (a) $7.9~\text{km/s}$
• (b) $9.8~\text{km/s}$
• (c) $11.2~\text{km/s}$
• (d) $5.6~\text{km/s}$

Answer: (c) $11.2~\text{km/s}$.

Q4. According to Kepler’s third law, the square of the time period is proportional to:

• (a) Cube of semi-major axis
• (b) Square of semi-major axis
• (c) Fourth power of semi-major axis
• (d) Inverse of semi-major axis

Answer: (a) Cube of semi-major axis.

Q5. The orbital velocity of a satellite just above Earth's surface is:

• (a) $7.9~\text{km/s}$
• (b) $11.2~\text{km/s}$
• (c) $3.6~\text{km/s}$
• (d) $5.0~\text{km/s}$

Answer: (a) $7.9~\text{km/s}$.

2. Very Short Answer (VSA).

Q1. State Newton’s universal law of gravitation.

Answer: Every particle attracts every other particle in the universe with a force directly proportional to the product of their masses and inversely proportional to the square of the distance between them.

Q2. What happens to the value of $g$ as we move from the surface to the center of the earth?

Answer: The value of $g$ decreases linearly and becomes zero at the center of the earth.

Q3. Define escape velocity.

Answer: Escape velocity is the minimum velocity required for an object to leave the gravitational influence of a planet without further propulsion.

Q4. Give the expression for gravitational potential at a distance $r$ from mass $M$.

Answer: Gravitational potential at distance $r$ is $V = -\dfrac{GM}{r}$, where $G$ is the universal gravitational constant.

Q5. State Kepler’s first law.

Answer: The path of every planet is an ellipse with the Sun at one of its foci.

3. Short Answer Questions.

Q1. Explain how acceleration due to gravity changes with altitude above Earth's surface.

Answer: As altitude increases, the distance from the Earth's center increases, so acceleration due to gravity decreases according to $g' = g\left(1 - \dfrac{2h}{R}\right)$ for small heights $h$ compared to Earth's radius $R$. The farther from the surface, the less gravitational pull is experienced.

Q2. Derive the formula for the orbital velocity of a satellite just above Earth’s surface.

Answer:

1. Centripetal force is provided by gravitational force: $mg = \dfrac{mv^2}{R}$.
2. From $F = \dfrac{GMm}{R^2}$, set $\dfrac{mv^2}{R} = \dfrac{GMm}{R^2}$.
3. $v = \sqrt{\dfrac{GM}{R}}$.

Q3. What is the significance of gravitational potential energy being negative?

Answer: Negative gravitational potential energy means that work must be done by an external force to remove a mass from the gravitational field. It signifies that the object is bound to the planet or star and energy needs to be supplied to escape that attraction.

Q4. How does motion of a satellite differ in polar and geostationary orbits?

Answer: A geostationary satellite orbits above the equator with a period equal to Earth’s rotation (24 hours), appearing stationary over a point. Polar satellites pass over the poles, covering the whole Earth as it rotates, with much shorter periods.

Q5. State and briefly explain Kepler’s second law of planetary motion.

Answer: Kepler’s second law (law of areas) states that a line joining a planet and the sun sweeps out equal areas in equal time intervals. It implies that the planet moves faster when closer to the sun and slower when farther away.

4. True or False Questions.

Q1. The value of $g$ is maximum at the poles of the Earth.

Answer: True.

Q2. Kepler’s laws apply only to circular orbits.

Answer: False.

Q3. The work done in moving a body around the earth in a circular orbit is zero.

Answer: True.

Q4. Gravitational potential at infinity is zero.

Answer: True.

Q5. Escape velocity depends on the mass of the escaping object.

Answer: False.

3. Fill in the Blanks Questions.

Q1. The value of acceleration due to gravity at the center of the earth is ______.

Answer: Zero.

Q2. The energy required by a satellite to escape Earth’s gravitational field is called ______.

Answer: Escape energy.

Q3. The expression $V = -\dfrac{GM}{r}$ represents the ______ due to mass $M$ at distance $r$.

Answer: Gravitational potential.

Q4. Kepler’s first law states that planets move in ______ orbits with the sun at one focus.

Answer: Elliptical.

Q5. A satellite requires a ______ velocity to move in a stable circular orbit around the earth.

Answer: Critical/orbital.

Gravitation and Its Importance for NEET Physics Preparation

Learning Gravitation in Physics gives NEET aspirants the tools to solve questions related to Earth’s gravity, planetary motion, and satellites. This chapter builds the basics for more advanced topics and sharpens your logical thinking, which is highly useful for scoring well in the exam.

With Vedantu’s curated questions on the universal law of gravitation, Kepler’s laws, and gravitational potential, you will find it easy to practice application-based MCQs and conceptual NEET Physics numericals from this chapter. Regular practice supports efficient revision and clearer concepts.

Prepare with Vedantu to stay updated with the latest NEET Physics patterns. The Gravitation chapter plays an important role in linking motion, force, energy, and planetary systems, improving your confidence while answering NEET objective and short-answer questions in exams.