What are some of the most common materials that display the photoelectric effect?

the so-called alkali metals, the most used of all is potassium

Explanation:

The photoelectric effect is the expulsion of electrons from metals by effect of incident radiation.

To see this effect, materials with a small work function are needed, so the most used materials are the materials of group i of the periodic table, the so-called alkali metals, the most used of all is potassium

probably not the "magnets"in the magnet, so to speak, are thought to be electrons orbiting in shells. vurrent loops two sides to the loop