A planet is moving in an elliptical orbit aro | vedclass

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(C) The gravitational force is a conservative force. For any conservative force,the work done in a complete closed path (one complete revolution) is a

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(ii) and (iii) are true

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(C) The gravitational force is a conservative force. For any conservative force,the work done in a complete closed path (one complete revolution) is always zero.Thus,statement (iii) is true.Work done is given by the dot product $W = \int \vec{F} \cdot d\vec{r}$.Since $\vec{F} = m\vec{a}$,we have $W = \int m\vec{a} \cdot d\vec{r}$.If the acceleration vector $\vec{a}$ (which is directed towards the sun) is perpendicular to the displacement vector $d\vec{r}$ (which is tangent to the orbit),the work done is zero.In an elliptical orbit,there are specific points (at perihelion and aphelion) where the velocity is perpendicular to the radius vector,meaning the force is perpendicular to the displacement at those instantaneous points.Therefore,the work done is zero at these specific points,making statement (ii) true.Statement $(i)$ is false because work is zero at specific points.Statement (iv) is false because work is not zero for any arbitrary small part of the orbit.Hence,(ii) and (iii) are true.

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