Which of the following phenomena supports the particle nature of photons?
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → Photoelectric effect
Light behaves as a wave in some experiments and as a stream of particles, photons, in others. In the photoelectric effect, light falling on a metal knocks out electrons. Whether electrons come out depends on the frequency of the light, not its brightness, and they come out at once. Einstein explained this in 1905 by treating light as photons, each of energy \(h\nu\), each passing its energy to one electron: a particle picture.
Why the other options are incorrect
Option (1) Polarisation — Incorrect. It shows that light is a transverse wave, vibrating across its direction of travel.
Option (2) Diffraction — Incorrect. The bending of light round edges and small openings is wave behaviour.
Option (3) Interference — Incorrect. Bright and dark fringes come from waves adding and cancelling, as in Young’s double-slit experiment.