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Question
The square of its period of revolution around the sun is directly proportional to the ______ of the mean distance of a planet from the sun.
Options
square
square root
cube
cube root
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Solution
The square of its period of revolution around the sun is directly proportional to the cube of the mean distance of a planet from the sun.
Explanation:
Mathematically, T2 ∝ r3, so `T^2/r^3` is the same for all planets; if the mean distance r increases, the period T increases so that T2 grows as r3. This shows the period depends on the cube of the distance.
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