LEDs emit light when electrons recombine with holes in a semiconductor, releasing energy as:
- Heat
- Photons
- Phonons
- Plasmons
Answer: Photons
Electroluminescence in LEDs: electron-hole recombination across bandgap emits photons (light). Energy (color) determined by semiconductor bandgap (e.g., GaAsP for red). Energy-efficient lighting. [[NCERT Physics Class 12]]