Ionisation is the process of removing one or more electrons from an atom or molecule, resulting in a positively charged ion.
Ionisation can occur through various processes, such as exposure to high energy radiation, collisions with other particles, or through the absorption of photons.
The photoelectric effect is the phenomenon where electrons are emitted from a material when it is exposed to light of a certain frequency or higher.
The photoelectric effect is caused by the transfer of energy from the photons of light to the electrons in the material, which allows them to overcome the binding forces of the material and escape as free electrons.
The photoelectric effect has played a crucial role in the development of modern physics, as it provided evidence for the particle nature of light and helped establish the concept of discrete energy levels in atoms. It also has practical applications in technology, such as solar cells and photomultiplier tubes.