Q185 / 200 · MHT CET - Medical 2026 (26 April Shift 1) · Physics
Out of the following what is used to detect the intensity of light ?
- ALED in forward bias.
- BPhotodiode in forward bias.
- CLED in reverse bias.
- Correct answerDPhotodiode in reverse bias
Solution
A photodiode is a p-n junction diode fabricated with a transparent window to allow light to fall on the diode.
It is operated under reverse bias. When the photodiode is illuminated with light (photons) with energy greater than the energy gap of the semiconductor, electron-hole pairs are generated due to the absorption of photons.
Due to the electric field of the junction, electrons and holes are separated before they recombine. The magnitude of the photocurrent is directly proportional to the intensity of incident light.
Thus, a photodiode in reverse bias is used to detect the intensity of light.
Answer: Photodiode in reverse bias
It is operated under reverse bias. When the photodiode is illuminated with light (photons) with energy greater than the energy gap of the semiconductor, electron-hole pairs are generated due to the absorption of photons.
Due to the electric field of the junction, electrons and holes are separated before they recombine. The magnitude of the photocurrent is directly proportional to the intensity of incident light.
Thus, a photodiode in reverse bias is used to detect the intensity of light.
Answer: Photodiode in reverse bias
Hence, the correct answer is option: 'D'.