Question

15. According to the Kepler's laws a planet moves in an elliptic orbit with the sun at a focus of the ellipse. Taking the planet and the sun to be point masses the torque on the planet with respect to sun [Hint : As force is central t = 0] [ ] a) Is zero at all times b) varies with time c) can be non-zero but constant in time d) cannot be defined for an elliptical orbit​

Answer 1

a) Is zero at all times

because it is not applicable to eleptical orbit. so sun exert 0 torque.