Answer: halves.
- A halves
- B doubles
- C becomes four times
- D is unchanged
Correct answer: A. halves
Explanation: λ = h/p, so doubling p halves the wavelength.
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.