Photoelectric Effect - the Graph

The Photoelectric effect is summarised in the following equation:

hf= Φ + EK

hf is the energy of the photon (E = hf),

EK is the maximum kinetic energy of a released photoelectron and

Φ the work function is represented by the Greek symbol 'phi'.

so rearranging we get an equation of a straight line

EK = hf - Φ


maximum kinetic energy Ek as the dependent variable on the y axis

frequency f as the independent variable on the x axis

a gradient of the Planck constant

and a negative intercept of the work function


Click here to read about the photoelectric effect experiment and a bit of history of its discovery.
Click here to go to a page of videoclip explanations
Click here to go to the graph
Click here to go to stopping potential
Click here to go to A level standard questions on this topic