Answer: 4.8 × 10¹⁴ Hz.
- A 4.8 × 10¹⁴ Hz
- B 3.2 × 10¹⁵ Hz
- C 4.8 × 10¹⁵ Hz
- D 9.6 × 10¹⁴ Hz
Correct answer: A. 4.8 × 10¹⁴ Hz
Explanation: phi = hf₀. f₀ = phi/h = (2×1.6×10⁻¹⁹)/(6.6×10⁻³⁴) = 3.2×10⁻¹⁹/6.6×10⁻³⁴ ≈ 4.8×10¹⁴ Hz.
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.