Q.No.139: - Define phosphorescent also describe the factors upon which it depends.

Q.No.139: - Define phosphorescent also describe the factors upon which it depends.

Ans: - Objects that continue to glow longer than 10^-8s after the source of the excitation is removed are called phosphorescent and the material that causes this effect is called phosphor. For example, dial of clock. It depend on the duration of light emission after the source of excitation is removed.