The photoelectric effectEdexcel International A Level Physics: Flashcards

What these 12 flashcards ask

What is a photoelectron?
What is the work function?
What is the threshold frequency?
State the photoelectric equation.
How is threshold frequency related to work function?
What is 1 eV in joules?
What does doubling the intensity (same frequency) do?
What does a graph of maximum kinetic energy against frequency show?
Why is there no emission below the threshold frequency?
Why can an electron not add up energy from several photons?
What did the wave model predict that was not seen?
What does the photoelectric effect show about electromagnetic radiation?

Exam questions on The photoelectric effect

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
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
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

Written by the Exaim team, led by Shaun Daswani (Head of Upper Secondary, Improve ME Institute; MSc Financial Mathematics, Imperial College London; BSc, UCL) and Jason Daswani (operational lead, Improve ME Institute; LSE).