Question

A planet is moving around the sun with mean distance r and time period T, then 

(a) \(T \propto r^3\)

(b) \(T^2 \propto r^3\)

(c) \(T^2 \propto r^2\)

(d) \(T \propto r^2\)

Answer 1

Correct option is (b) \(T^2 \propto r^3\)

According to Kepler's third law of planetary motion, square of time period (T) is directly proportional to the cube of mean distance (r) between the planet and sun. i.e. \(T^2 \propto r^3\)