Photoconduction is the ability of a material to conduct which of the following when struck by light?

• A. Electrical current
• B. Heat
• C. Magnetic field
• D. Sound

Answer: (A)

Photoconduction is about how light enables electrical conductivity in a material. When photons hit a photoconductive material, their energy excites electrons and creates electron-hole pairs, adding more charge carriers to the system. With an electric field applied, these extra carriers allow current to flow more easily, so the material conducts electricity under illumination while its resistance drops in the dark. This behavior underpins photodetectors and photoresistors, where increasing light intensity raises conductivity.

Heat, magnetic effects, or sound aren’t what’s being measured here. Light can cause a thermal response (photothermal) by warming the material, but that changes temperature and resistance in a different way, not by generating additional charge carriers for conduction. Light doesn’t inherently produce a magnetic field that enables conduction, and while light can induce sound through photoacoustic effects, that is a mechanical response, not electrical conduction.