A thin equiconvex lens of refractive index $\mu_1 = 1.5$ and radius of curvature $R$ is placed on a horizontal plane mirror. When a space between the lens and the mirror is filled with a liquid of refractive index $\mu_2$, the focal length of the combination is found to be $2R$. The value of $\mu_2$ is:
Topic: Ray Optics | Source: AI Generated (JEE Main)