Plane mirrors and are kept at angle with respect to each other. Light falls on is reflected then falls on and is reflected. The emergent ray is opposite to the incident direction. The angle is equal to

Light or visible light is electromagnetic radiation that can be perceived by the human eye. Visible light is usually defined as having wavelengths in the range of 400–700 nanometres, corresponding to frequencies of 750–420 terahertz, between the infrared and the ultraviolet.