Q 11-07-079JEE MainJEE Main 2023 (29 Jan, Shift 2)Easy
The time period of a satellite of earth is $24$ hours. If the separation between the earth and the satellite is decreased to one fourth of the previous value, then its new time period will become
Answer: (D) 3 hours
By Kepler's third law $T\propto r^{3/2}$:
$$T'=24\times\left(\frac14\right)^{3/2}=\frac{24}{8}=3\ \text{hours}$$
Solution by Sreeraj P, M.Sc Physics