Question

Which of the following equation describes, Kepler's third law?
1. T ∝ R²
2. T ∝ R3
3. T ∝ R^2/3
4. T ∝ R3/2

Answer 1

Correct Answer - Option 4 : T ∝ R3/2

CONCEPT:

• Kepler's Third Law: The square of the time period of a planet is directly proportional to the cube of the distance of its orbit.

T2 α R3

where T is the time period and R is the mean distance of the planet from the sun.

EXPLANATION:

According to Kepler's Law, planets' time period varies with their radius as given below:

T2 α R3

i.e. T ∝ R3/2

So the correct answer is option 4.