The photoelectric effectEdexcel International A Level Physics: Mind map

Exam questions on The photoelectric effect

1. A student shines ultraviolet light on to a clean zinc plate connected to a sensitive charge detector and finds that electrons are emitted from the plate. When she replaces the ultraviolet lamp with a very bright red lamp, no electrons are emitted, however bright the lamp is made.
   Explain why no electrons are emitted by the bright red lamp.2 marks
2. A clean sodium surface has a work function of 2.3 eV. It is illuminated with light of wavelength 400 nm. Use the Planck constant h = 6.63 × 10⁻³⁴ J s, the speed of light c = 3.00 × 10⁸ m s⁻¹ and 1 eV = 1.60 × 10⁻¹⁹ J.
   Calculate the maximum kinetic energy of the photoelectrons emitted by the 400 nm light.2 marks
3. A metal Q has a work function of 3.6 × 10⁻¹⁹ J. It is illuminated with light of frequency 6.0 × 10¹⁴ Hz. Use the Planck constant h = 6.63 × 10⁻³⁴ J s and the electron mass m = 9.11 × 10⁻³¹ kg.
   Calculate the maximum kinetic energy of the photoelectrons.3 marks