Fluorescence is the property of absorbing radiant energy of ...... frequency and re-emitting energy of _ frequency in the visible region of electromagnetic spectrum.

Explanation

In fluorescence, a photon is absorbed which takes an atom or molecule to a higher energy level. To conserve momentum, this higher level of energy might consist of a combination of electronic transition, rotational transition, vibrational transition, and kinetic energy. The atom or molecule may remain in a higher energy state for a long enough period of time to collide with other atoms or molecules and transfer some of the energy to them. When a photon of lower energy is emitted, the remaining energy may also be emitted as a photon, but it is unlikely that the energy and momentum can both be conserved, so much of the time the energy remains in the molecule until a collision happens to exchange the energy by means of a collision. Eventually, a low-energy photon is emitted, but by then some of the energy has become part of the internal energy of the material, raising its temperature ever so slightly. So, some energy is released as a second photon and some of the energy contributes to heating up the fluorescent material.