Question
What is the photovoltaic effect?
Answer Options
- A) The conversion of voltage to current when exposed to light
- B) The conversion of light to electrical energy
- C) The effect that causes a photodiode to emit light when a voltage is applied
- D) The effect that causes a phototransistor’s beta to decrease when exposed to light
Correct Answer: B
Explanation
The term ‘photovoltaic’ is derived from ‘photo’ (light) and ‘voltaic’ (producing electricity). It describes the physical process that occurs within a semiconductor junction when exposed to light, specifically at the heart of a solar cell or photodiode.
The photovoltaic effect is defined as the conversion of light to electrical energy. When photons strike the semiconductor material, they knock electrons loose from the crystal lattice, creating a charge imbalance (an electron-hole pair) that results in the generation of a voltage across the junction. If an external circuit is connected, this voltage drives a current.
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