NEET Physics: Kepler’s law of planetary motion Practice Questions
15 free multiple-choice questions on Kepler’s law of planetary motion (Gravitation) for NEET Physics, each with the correct answer and a step-by-step explanation. Attempt a question, then reveal the solution to check your reasoning.
Practice thousands more NEET questions in the app →Q1. Which of the following statements correctly describes the relationship between the orbital period and the semi-major axis for a satellite orbiting a fixed body according to Kepler's Third Law?
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Correct answer: C — The period is directly proportional to the square of the semi-major axis
Kepler’s Third Law (when applied to orbital motion) states that the square of the orbital period (T) is directly proportional to the cube of the semi-major axis (a) of the orbit (T² ∝ a³).
Q2. Which geometric shape describes the orbit of a planet around the Sun according to Kepler's laws?
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Correct answer: A — Ellipse
Kepler's first law states that the orbit of a planet is an ellipse, with the Sun at one focus.
Q3. Which statement correctly describes Kepler’s Third Law?
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Correct answer: A — The orbital period is directly proportional to the cube of the semi-major axis.
Kepler's Third Law states that the square of the orbital period is proportional to the cube of the semi-major axis (T² ∝ a³).
Q4. If a satellite moves in a circular orbit, which Kepler's law is most directly applicable to its motion?
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Correct answer: A — Law of Periods
While Kepler's laws apply to elliptical orbits, the concept of orbital period (Law of Periods) is central to defining the motion of any orbiting body.
Q5. The relationship T² ∝ a³ (where T is the orbital period and a is the semi-major axis) is derived from which of Kepler's Laws?
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Correct answer: C — Third Law
The relationship T² ∝ a³ is the mathematical formulation of Kepler's Third Law of Planetary Motion.
Q6. The rate at which a body sweeps out area is constant in an elliptical orbit. This is a direct consequence of which of Kepler's laws?
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Correct answer: B — Second Law
Kepler's second law specifically deals with the proportional relationship between the area swept and the time taken, defining the conservation of angular momentum in orbital mechanics.
Q7. The ratio of the square of the orbital period (T) to the cube of the semi-major axis (a) for any planet in a fixed elliptical orbit is proportional to:
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Correct answer: A — The mass of the planet
Kepler's Third Law relates the square of the period (T²) to the cube of the semi-major axis (a³). Thus, the ratio T²/a³ is constant (proportional to GM/4π²).
Q8. If the orbital period of a satellite orbiting the Earth were to increase, what would happen to the distance of the satellite from the Earth, assuming the mass of the Earth is constant?
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Correct answer: A — The distance increases
Based on Kepler's Third Law (T² ∝ a³), if the period (T) increases, the semi-major axis (distance) must also increase.
Q9. Kepler's Second Law of planetary motion is fundamentally based on which physical principle?
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Correct answer: B — Conservation of angular momentum
The second law states that a line joining a planet and the Sun sweeps out equal areas in equal intervals of time, which is a direct consequence of the conservation of angular momentum.
Q10. In an elliptical orbit, the distance between the planet and the Sun is maximum at:
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Correct answer: B — Aphelion
Aphelion is the point in the orbit where the planet is farthest from the Sun (the focus of the ellipse).
Q11. According to Kepler's First Law of Planetary Motion, the orbit of a planet around the Sun is:
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Correct answer: A — An ellipse
Kepler's First Law states that the orbit of a planet is an ellipse, with the Sun at one of the foci of the ellipse.
Q12. Kepler’s first law states that the orbit of a planet is an ellipse with the Sun at one focus. The shape of the orbit (ellipse) is determined by which physical principle?
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Correct answer: B — Conservation of angular momentum
Kepler's first law defines the shape of the orbit as an ellipse. This elliptical shape is a direct consequence of the inverse square law of gravitational force and the resulting orbital mechanics.
Q13. Which property of an elliptical orbit is directly related to the difference between the semi-major axis and the semi-minor axis?
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Correct answer: B — Eccentricity
The eccentricity (e) of an elliptical orbit determines the shape. It is mathematically defined in terms of the major axis (related to the semi-major axis) and the minor axis (related to the semi-minor axis).
Q14. According to Kepler’s second law of planetary motion, the line joining the Sun and a planet sweeps out equal areas in equal intervals of time. This law is directly related to which property of the orbit?
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Correct answer: A — Angular momentum
Kepler’s second law states that a line joining a planet and the Sun sweeps out equal areas during equal intervals of time. This directly relates to the conservation of angular momentum in orbital motion.
Q15. The area swept by the line joining a planet and the Sun in a fixed time interval is directly proportional to which of the following quantities?
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Correct answer: C — The orbital period
According to Kepler's second law, the area swept is proportional to the time interval. If the time interval is fixed, the area swept is directly proportional to the orbital period (as the rate of sweeping is constant).
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