Waves

In an experiment to determine the period of a simple pendulum of length 1 m, it is attached to different spherical bobs of radii r₁ and r₂ . The two spherical bobs have uniform mass distribution. If the relative difference in the periods, is found to be 5×10^−4 s, the difference in radii, $\left| {} \right.$r₁ $-$ r₂ $\left| {} \right.$ is best given by :