Photoelectric Effect Lab for A Level Physics

Watch photoelectrons emerge with different energies, then use a reversible electric field to accelerate, slow and stop them.

Learning guide and suggested activities

What this tool shows

Why photoemission depends on photon frequency rather than light intensity alone
How work function, threshold frequency, maximum kinetic energy and stopping potential are linked
How a current–potential curve reveals stopping potential and saturation current
How stopping-potential data can be used to estimate the Planck constant

OCR A relevance

OCR A H556 Module 4.5.2: the photoelectric effect and photon interactions
Work function, threshold frequency and stopping potential
hf = φ + Eₖ(max) and Eₖ(max) = eVₛ

AQA relevance

AQA 7408 section 3.2.2.1: the photoelectric effect
Photon energy, work function and threshold frequency
hf = φ + Eₖ(max) and Eₖ(max) = eVₛ

Try these tasks

Change wavelength and intensity to compare electron energy with emission rate.
Explain why electrons emitted from different depths emerge with different kinetic energies.
Reverse the collector polarity and observe electrons accelerate, slow or turn back.
Find the stopping potential from the photocurrent and explain what is stopped.
Use a stopping-potential graph to explain how Planck's constant can be estimated.