MCQs on Photodiode
Q: Photodiodes operate by absorption of photons or charged particles and generate a flow of current in an external circuit,……….. to the incident power. The light is absorbed ……….with distance and is ………..to the absorption coefficient.
- Proportional, exponentially, proportional
- Proportional, logarithmically, inversely proportional
- Inversely proportional, exponentially, unrelated
Answer: (1) Proportional, exponentially, proportional
Q: What is the reason phototransistor produces more current than a photodiode?
- A wider spectrum is accepted by the phototransistor than the photodiode
- The current produced by photons is amplified by the hfe of the transistor
- The phototransistor can heavily doped than the photodiode
- At low light conditions, a photodiode is used.
Answer: (3) The current produced by photons is amplified by the hfe of the transistor
Q: In a photodiode, when there is no incident light, the reverse current is almost negligible and is called
- Zener current
- Dark current
- Photocurrent
- PIN current
Answer: (2) Dark current
Q: Compared to a photo-diode, which of the listed advantages and disadvantages would be expected of a phototransistor
- Faster response and greater sensitivity
- Faster response and less sensitivity
- Slower response and greater sensitivity
- Slower response and less sensitivity
Answer: (3) Slower response and greater sensitivity
Q: When a diode is forward biased, the recombination of free electron and holes produce
- Heat
- Light
- Radiation
- All the above
Answer: (4) All the above
Q: The width of the depletion region is
- Directly proportional to the doping
- inversely proportional to the doping
- Independent of doping
- None of the above
Answer: (2) inversely proportional to the doping
Q: Photodiode is used in the detection of
- Visible light
- Invisible light
- No light
- Both visible and invisible light
Answer: (4) Both visible and invisible light
Q: In using a photodiode as a photodetector, it is invariably reverse biased
- The power consumption is much reduced compared to reverse biased condition
- Only when the photodiode is reverse biased the incident photons produce electron-hole pairs
- Only if the diode is reverse biased light variations can be converted into current variations
- When photons are incident on the diode, the fractional change in the reverse current is much greater than the fractional change in the forward current
Answer: (4) When photons are incident on the diode, the fractional change in the reverse current is much greater than the fractional change in the forward current.
Q: The maximum wavelength of photons that can be detected by a photodiode made by a semiconductor of bandgap 2eV is about
- 620 nm
- 700 nm
- 740 nm
- 1240 nm
Answer: (1) 620 nm
Q: The presence of dark current decreases the sensitivity of the photodiode to light
- True
- False
Answer: (1) True