Explanation

Dispersion by a Prism: If a prism is placed in a room and a narrow beam of white light is allowed to fall on one of its refracting faces, it is found that light coming out from the other face of the prism is split in to seven colors i.e violet, indigo, blue, green, yellow, orange and red . This phenomenon is called dispersion at light. The phenomenon of splitting of white light into its seven constituent colors is called dispersion of light.