Photoelectric Effect

The photoelectric effect is where light will hit a material like a metal and the material will release an electron. We can apply a small voltage and have a wire or rod to collect the electrons and measure the flowing current.

To free an electron from a material to a vacuum, there is some minimum amount of energy required called the work function $\phi$.

We can describe the max kinetic energy as an electron is freed as

\[KE_\text{max} = hf - \phi\]

We can also say about light intensity,

\[I_av = \frac{\text{# photos}}{\text{surface area}} \times hf\]