Question

Fluoroscence differs from phosphorescence in being

• A. Delayed emission
• B. Instant emission
• C. Bioluminescence
• D. Chemiluminescence

Answer 1

The correct option is B Instant emission

Fluorescence is the phenomenon of absorption of energy by molecule or atom and instant emission of a photon of light or electromagnetic radiation after being excited to a higher quantum state. In this, time interval between absorption and emission of energy is very short. Unlike fluorescence, phosphorescence does not show instant emission of radiation. In this, excitation of electrons is accompanied with the change of a spin state. In this, the time interval between absorption and emission of energy is comparatively longer.

Thus, the correct answer is option B.