_____ cell converts light energy directly into electric energy.
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → Photovoltaic
A photovoltaic cell (solar cell) is made of a semiconductor such as silicon. When light falls on it, it produces a voltage across its junction by the photovoltaic effect, so it turns light energy directly into electric energy without any moving parts or an outside source.
Why the other options are incorrect
Option (2) Photoelectric — Incorrect. A photoelectric cell (photocell) releases electrons when light falls on it and is used as a light sensor that switches a current from a battery, as in automatic doors and burglar alarms.
Option (3) Photothermal — Incorrect. A photothermal device turns light into heat, as in a solar water heater.
Option (4) Photocatalytic — Incorrect. A photocatalyst such as titanium dioxide uses light to speed up a chemical reaction; it produces no electric energy.