What is spontaneous emission? Explain in brief.

Spontaneous emission:

a. This is the process by that a light source as like an atom, molecule, nano-crystal or nucleus into an excited state undergoes a transition to the ground state and then emits a photon.

b. The atoms into the excited state drop to the lower energy state after they have stayed within the excited state for a short duration of time known their life time.

c. Throughout this process photons of energy hν = E₂ - E₁, that is energy difference in between the two states of the atom, those are emitted.

d. Spontaneous emission of light or luminescence is a basic process which plays a necessary role in various phenomena into nature and forms the basis of several applications, as like fluorescent tubes, plasma display panels, television screens, lasers and light emitting diodes.