The period of revolution of planet A round from the sun is 8 times that of B. The distance of A from the sun is how many times greater then tht of B from the sun ?

Options

A. 2
B. 4
C. 3
D. 5

Answer

C

Explanation

As `T_(2) prop r^(3)`
so `(T_(A)^(2))/(T_(B)^(2))=(r_(A)^(3))/(r_(B)^(3))` or `(r_(a))/(r_(B))=(T_(A))/(T_(B))^(2//3)=(8)^(2//3)=4 rarr r_(A)=4r_(B)`
so `r_(A)-r_(B)=4r_(B)-r_(B)=3r_(B)`