Q. In an experiment to determine the period of a simple pendulum of length $1\, m$, it is attached to different spherical bobs of radii $r_1$ and $r_2$. The two spherical bobs have uniform mass distribution. If the relative difference in the periods, is found to be $5 \times 10^{-4} s$, the difference in radii, $ | r_1 - r_2|$ is best given by :
Solution: