Led Emission Principle
Mediumphysics
LED emits light when?
Select the correct option:
Solution
Incorrect! Answer:
Forward biased causing recombination
- LED Core: A Light Emitting Diode is a heavily doped PN junction made from compound semiconductors like GaAsP.
- Mechanism: Under forward bias, electrons from the N-side and holes from the P-side are injected into the junction region.
- Recombination: In the junction, free electrons 'fall' into vacancies (holes). During this recombination process, energy is released.
- Photon Emission: In these specific materials (direct band gap), the released energy appears in the form of photons of light.
- Calculation: The wavelength of light depends on the energy gap (Eg=hf=hc/λ).
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About This Question
- Subject
- physics
- Chapter
- semiconductor devices
- Topic
- led emission principle
- Difficulty
- Medium
- Year
- 2025
Solution
Correct Answer:
Forward biased causing recombination
- LED Core: A Light Emitting Diode is a heavily doped PN junction made from compound semiconductors like GaAsP.
- Mechanism: Under forward bias, electrons from the N-side and holes from the P-side are injected into the junction region.
- Recombination: In the junction, free electrons 'fall' into vacancies (holes). During this recombination process, energy is released.
- Photon Emission: In these specific materials (direct band gap), the released energy appears in the form of photons of light.
- Calculation: The wavelength of light depends on the energy gap (Eg=hf=hc/λ).
This medium difficulty physics question is from the chapter semiconductor devices, covering the topic of led emission principle. It appeared in the 2025 exam.
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