IGNOU MPHE 25 2026 - What is luminescence of a material? Differentiate between fluorescence

Question

What is luminescence of a material? Differentiate between fluorescence and phosphorescence.

19 Jan 2026

Answer :

Word Count : 284

Luminescence is the phenomenon by which a material emits light as a result of electronic excitation without a corresponding rise in temperature. It occurs when electrons in a material absorb energy from an external source such as ultraviolet radiation, X-rays, electric fields, or chemical reactions, and are promoted to higher energy states. When these excited electrons return to lower energy or ground states, the excess energy is released in the form of visible or near-visible electromagnetic radiation. In materials science, luminescence is important for understanding electronic band structure,

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