The photoelectric effect is a scientific phenomenon in which electrons are emitted from a material surface when it is exposed to electromagnetic radiation, such as light. The energy from the radiation is transferred to the electrons in the material, causing them to be ejected from the surface. The effect was first observed by Heinrich Hertz in 1887, and explained by Albert Einstein in 1905 using the concept of photons. The photoelectric effect is used in many fields, including electronics, solar