Question

Assertion : The square of the period of revolution of a planet is proportional to the cube of its distance from the sun. 

Reason : Sun’s gravitational field is inversely proportional to the square of its distance from the planet.

(A) If both Assertion and Reason are true and the Reason is correct explanation of assertion 

(B) If both Assertion and Reason are true, but reason is not correct explanation of the Assertion 

(C) If Assertion is true, but the Reason is false 

(D) If Assertion is false, but the Reason is true 

Answer 1

Correct option: (B)

Explanation:

By keepler’s law, T² ∝ R³ 

where T is period of revolution

R is distance from sun.

Also gravitational field ∝ [1 / (distance)²]

hence both statements are correct but reason is not explanation of assertion.