Question

The period of revolution of planet A around the sun is 8 times that of B. The distance of A from the sun is how many times greater than that of B from the sun

• A. 2
• B. 3
• C. 4
• D. 5

Answer 1

Answer: (C)

4

Answer 2

$\frac { T _ { A } } { T _ { B } } = \left( \frac { r _ { A } } { r _ { B } } \right) ^ { 3 / 2 }$ $\Rightarrow 8 = \left( \frac { r _ { A } } { r _ { B } } \right) ^ { 3 / 2 }$ $\Rightarrow r _ { A } = ( 8 ) ^ { 2 / 3 } r _ { B }$