1) Photoconduction 
Photoconductivity is an optical and electrical phenomenon in which a material becomes more electrically conductive due to the absorption of electromagnetic radiation such as visible light, ultraviolet light, infrared light, or gamma radiation. When light is absorbed by a material such as a semiconductor, the number of free electrons and electron h...
the increase in the electrical conductivity of semiconductors and insulators when they are exposed to light of sufficient energy. Photoconductivity ... [6 related articles]
[n] - change in the electrical conductivity of a substance as a result of absorbing electromagnetic radiation
photoconductivity, photoconduction 1. Electrical conductivity affected by exposure to light. 2. An effect observed in many substances, in which the electrical conductivity is increased when the substance is exposed to electromagnetic radiation, usually in the visible region of the light spectrum.
photoconduction noun change in the electrical conductivity of a substance as a result of absorbing electromagnetic radiation