Refraction of Light at a Spherical Surface #8211; On the spherical mirror is incident object an object a ray of light. This formula is applied to both the surfaces, i.e. concave and convex. [μ<sub>2</sub>/v #8211; μ<sub>1</sub>/u = μ<sub>2</sub> #8211; μ<sub>1</sub>/R]