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Semiconductor Electronic: Material, Devices And Simple Circuits — Physics STD 12 Science — Question

Gujarat BoardEnglish MediumSTD 12 SciencePhysicsSemiconductor Electronic: Material, Devices And Simple Circuits1 Mark
MCQ
LED is a p-n junction diode which is:
  • A
    Forward biased.
  • B
    Either forward biased or reverse biased.
  • C
    Reverse biased.
  • D
    Neither forward biased nor reverse biased.
✓

Answer

  1. Forward biased.

Explanation:

An LED is a light emitting diode. The LED emits light when it is forward biased and it emits no light when it is reverse biased. The intensity of light is proportional to the square of the current flowing through the device.

When a junction diode is forward biased, energy is released at the junction due to recombination of electrons and holes. In the junction diode made of gallium arsenide or indium phosphide, the energy is released in visible region. Thus, light is emitted form the diode and hence the name 'light emitting diode'.

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