Which one of the following statement is not correct in the case of light emitting diodes?
A.It is a heavily doped p-n junction.
B.It emits light only when it is forward biased.
C.It emits light only when it is revers biased.
D.The energy of the light emitmited is equal to or slightly less than the energy gap of the semiconductor used.
Choose the correct answer from the options given below :

Options

A. `B`
B. `C`
C. `A`
D. `C and D`

Answer

To solve the question regarding which statement is not correct about light-emitting diodes (LEDs), let's analyze each option step by step.

### Step 1: Analyze Option A
**Statement A:** "It is a heavily doped p-n junction."
- **Explanation:** Light-emitting diodes are indeed formed from a p-n junction that is heavily doped. This allows for efficient recombination of charge carriers (electrons and holes), which is essential for light emission.
- **Conclusion:** This statement is correct.

### Step 2: Analyze Option B
**Statement B:** "It emits light only when it is forward biased."
- **Explanation:** LEDs emit light when they are forward biased. In this condition, electrons from the n-type region recombine with holes in the p-type region, releasing energy in the form of light.
- **Conclusion:** This statement is correct.

### Step 3: Analyze Option C
**Statement C:** "It emits light only when it is reverse biased."
- **Explanation:** This statement is incorrect. LEDs do not emit light when reverse biased; in fact, reverse bias can lead to breakdown and damage the LED. Light emission occurs only during forward bias.
- **Conclusion:** This statement is not correct.

### Step 4: Analyze Option D
**Statement D:** "The energy of the light emitted is equal to or slightly less than the energy gap of the semiconductor used."
- **Explanation:** The energy of the emitted light corresponds to the energy band gap of the semiconductor material used in the LED. This statement is accurate as the emitted photon energy is related to the band gap energy.
- **Conclusion:** This statement is correct.

### Final Conclusion
Based on the analysis:
- Option A is correct.
- Option B is correct.
- Option C is not correct.
- Option D is correct.

Thus, the answer to the question is **Option C**: "It emits light only when it is reverse biased."

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