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Assertion : Light emitting diode (LED) e...

Assertion : Light emitting diode (LED) emits spontaneous radiation.
Reason : LED are forward biased p-n junctions.

A

If both assertion and reason are true and reason correct explanation of assertion.

B

If both assertion and reason are true but reason the correct explanation of assertion.

C

If assertion is true but reason is false.

D

If both assertion and reason are false.

Text Solution

Verified by Experts

The correct Answer is:
A
When a junction dipole is forward biased as shown in figure, energy is released at the junction due to recombination of electrons and hole. In the junction dipole made of gallium arsenide or indium phosphide, the energy is released in visible region. Such a junction dipole is called light emitting dipole or `LED`. the radiated enegry emitted by `LED` is equal or less than the band gap of semiconductor.
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Knowledge Check

  • A: Light emitting diode(LED) emits spontaneous radiation. R: LED are forward biased p-n junctions.

    A
    If both Assetion & Reason are true and the reason is the not the correct explanation of the assertion , then mark (1)
    B
    if both Assertion & Reason are true but the reason is not the correct explanation of the assertion ,then mark (2)
    C
    If Assertion is true statement but reason is false, then mark (3).
    D
    If both Assertion and reason are false statements, then mark (4)

  • The light emitting diode (LED),

    A
    is made from the semiconducting compound gallium arsenide phosphide
    B
    emit light when forward biased
    C
    is made from one of the two basic semiconducting materials, silicon or germanium
    D
    emit light when reverse biased.

  • When LED is forward biased, then

    A
    electrons from the n-type material cross the p-n junction
    B
    electrons and holes neutralise each other
    C
    at junction electrons and holes remains at rest
    D
    None of the above

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    Name the p-n junction diode which emits spontaneous radiation when forward biased.

    In forward biasing of the p-n junction:

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    In forward biasing of the p-n junction

    Application of a forward biase to a p-n junction:

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