Physics · Gravitation

JEE Main 2025 — 7 April, Evening Shift — Question 56

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).

Assertion (A): The radius vector from the Sun to a planet sweeps out equal areas in equal intervals of time and thus areal velocity of planet is constant.

Reason (R): For a central force field the angular momentum is a constant.

In the light of the above statements, choose the most appropriate answer from the options given below.

  1. Option A:

    Both (A) and (R) are correct but (R) is not the correct explanation of (A)

  2. Option B:

    (A) is correct but ( RR ) is not correct

  3. Option C:

    Both (A) and (R) are correct and (R) is the correct explanation of (A)

    Correct
  4. Option D:

    (A) is not correct but ( RR ) is correct

Answer: C

Step-by-step solution

From Kepler's 2nd 2^{\text {nd }} law dAdt=L2m=\frac{d A}{d t}=\frac{L}{2 m}= constant and angular momentum

for central force is constant. so, both (A) and (R) are correct and (R) explain (A)

Answer key and solution verified before publishing.

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Exam
JEE Main 2025
Subject
Physics
Chapter
Gravitation
Topic
Planetary Motion & Binary Star System (Kepler's Law)
Given below are two statements: one is labelled as Assertion (A) and… | JEE Main 2025 PYQ with Solution · DhiX AI