Photochemistry is the study of chemical reactions that occur as a result of light absorption. The underlying process for all of photobiology is photochemistry. A molecule's electronic structure changes when it absorbs a photon of light, and it responds differently with other molecules as a consequence. The absorbed energy from light might cause photochemical changes in the absorbing molecule or in a nearby molecule (e.g., photosensitization).
Photobiology is a comprehensive term that encompasses all biological processes that include non-ionizing radiation. Photobiological responses are known to be the outcome of chemical and/or physical changes in biological systems caused by non-ionizing radiation. Photobiology is dominated by the formation of oxidants by electronic excitation via impinging light.
The study of electricity and how it affects chemical reactions is known as electrochemistry. Electricity is generated in electrochemistry by the passage of electrons from one element to another in a redox or oxidation-reduction reaction.