The phenomenon of having a continuous glow of a beam on the screen even after it is removed is called as a. fluorescence b.persistence c.phosphorescence d.incandescence e.None of these
The phenomenon of having a continuous glow of a beam on the screen even after it is removed is called as phosphorescence. Explanation: Phosphorescence is luminescence that occurs when energy is supplied by electromagnetic radiation usually UV rays. In this, light is absorbed by a material, which increase the energy level of electrons. Energy of light is not matched with electrons. Transition between lower energy and higher energy takes time but when occur, light released. As, this is a slow process, in between this time, a phosphorescent material appears to glow in dark. Phosphorescence release the stored energy slowly. It charged while exposing to light. Energy is stored for some time and then slowly released.
