Photons and the photoelectric effect Quiz
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5 questions, one answer each
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1. Which quantity is directly proportional to the energy of a photon?
- A. Wavelength
- B. Frequency
- C. Intensity
- D. Speed in a vacuum
2. Ultraviolet radiation causes photoelectric emission from a metal, but bright red light does not. What is the best explanation?
- A. Red light has less energy per photon than the work function, whatever the intensity
- B. Red light cannot be absorbed by the metal
- C. Red photons are too numerous to be absorbed
- D. Red light travels too slowly to eject electrons
3. A metal has a work function of 3.0 × 10⁻¹⁹ J. What is its threshold frequency? (h = 6.63 × 10⁻³⁴ J s)
- A. 2.0 × 10⁻⁵² Hz
- B. 4.5 × 10¹⁴ Hz
- C. 2.2 × 10¹⁵ Hz
- D. 1.1 × 10¹⁴ Hz
4. The intensity of radiation above the threshold frequency is doubled. What happens?
- A. No electrons are emitted until later
- B. The threshold frequency halves
- C. The number of photoelectrons per second doubles
- D. The maximum kinetic energy doubles
5. An electron is accelerated through a potential difference of 5.0 V. What energy does it gain, in joules?
- A. 8.0 × 10⁻²⁰ J
- B. 3.1 × 10¹⁹ J
- C. 5.0 J
- D. 8.0 × 10⁻¹⁹ J