Two planets move around the sun. The periodic times and the mean radii of the orbits are T1, T2, r1 and r2 respectively. The ratio of $\frac{T_1}{T_2}$ is equal to
Answer & explanation
Correct answer: option 4
$\frac{T_1^2}{T_2^2}=\frac{r_1^3}{T_2^3} ; \frac{T_1}{T_2}=\left(\frac{r_1}{r_2}\right)^{3 / 2}$