Kepler’s Law of Planetary Motion NEET Questions

Physics - Gravitation

Kepler’s Law of Planetary Motion MCQ Questions


13.
The square of the time period of revolution of a planet is proportional to the cube of the semi-major axis of its orbit. This is:

NEET - 2023

A.
Kepler’s first law
B.
Kepler’s second law
C.
Kepler’s third law
D.
Newton’s law of gravitation
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ANSWER :
C. Kepler’s third law
14.
Kepler's Second Law (Law of Areas) states that:
A.
A planet moves faster when farther from the Sun and slower when nearer
B.
The line joining a planet to the Sun sweeps equal areas in equal intervals of time
C.
The orbital speed of a planet is proportional to its distance from the Sun
D.
The area swept is proportional to the square of the time interval
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ANSWER :
B. The line joining a planet to the Sun sweeps equal areas in equal intervals of time
15.
The Law of Areas (Kepler's Second Law) is a consequence of:
A.
Newton's third law of motion
B.
Conservation of kinetic energy
C.
Conservation of angular momentum for any central force
D.
Conservation of linear momentum
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ANSWER :
C. Conservation of angular momentum for any central force
16.
Using the Law of Areas, if r_P and v_P are the distance and speed at perihelion, and r_A and v_A at aphelion, the relation between them is:
A.
v_P / v_A = r_A / r_P (since L = mr·v is conserved when r ⊥ v at apsides)
B.
v_P / v_A = r_P / r_A
C.
v_P × r_P² = v_A × r_A²
D.
v_P = v_A (speed is constant throughout orbit)
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ANSWER :
A. v_P / v_A = r_A / r_P (since L = mr·v is conserved when r ⊥ v at apsides)
17.
A planet moves around the Sun in an elliptical orbit. The ratio of its maximum to minimum speed is:

NEET - 2018

A.
1
B.
2
C.
1.5
D.
Depends on mass of planet
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ANSWER :
B. 2
18.
A planet at perihelion (closest point) has speed v_P and distance r_P from the Sun. At the aphelion r_A = 3r_P. The speed at aphelion is:
A.
v_A = v_P/3
B.
v_A = 3v_P
C.
v_A = v_P/9
D.
v_A = v_P√3
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ANSWER :
A. v_A = v_P/3