Answer: Photons have momentum.
- A Light is mainly a wave
- B Photons have momentum
- C Electrons have wave nature
- D Mainly electrons scatter X-rays
Correct answer: B. Photons have momentum
Explanation: Compton effect: X-ray photons scattered by electrons change wavelength. This proves photons carry momentum p = h/lambda.
In the photoelectric setup, light striking the metal plate ejects electrons that cross the evacuated tube to the collector, producing a measurable current on the ammeter.
Concept context
Photoelectric effect, de Broglie waves, Bohr's model, atomic spectra.