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# Figure (11-Q2) shows the elliptical path of a planet about the sun. The two shaded parts have equal area. If t_{1} and t_{2} be the time taken by the planet to go from a to b and from c to d respectively.

A. t_{1} < t_{2}.

B. t_{1} = t_{2}.

C. t_{1} > t_{2}.

D. Insufficient information to deduce the relation between t_{1} and t_{2}.

Answer :

From Kepler’s second law we know that a planet on a closed orbit sweeps equal areas in equal time. Hence, if the areas are equal, the time taken while traversing the arc enclosing the area will also be equal. Therefore, t_{1} = t_{2}.

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