Answer: Lower energy (longer wavelength).
- A Exactly the same energy as before the collision
- B Higher energy than the incident photon had
- C Lower energy (longer wavelength)
- D Exactly the same wavelength as before the collision
Correct answer: C. Lower energy (longer wavelength)
Explanation: Compton effect: photon transfers momentum to electron and loses energy. Scattered photon has longer wavelength (lower energy).
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.