Answer: High-energy electrons hit a metal target.
- A Electrons are emitted from metal according to conventional understanding
- B High-energy electrons hit a metal target
- C Photons hit metal in routine practice
- D Alpha particles are emitted overall
Correct answer: B. High-energy electrons hit a metal target
Explanation: X-rays: produced when fast electrons decelerate suddenly in metal target (bremsstrahlung) or when inner electrons are knocked out.
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.