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The special purpose diode operated / working under forward bias is/are

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Important Questions on Semiconductor Devices

MEDIUM
Physics>Modern Physics>Semiconductor Devices>Light Emitting Diode (LED)

Which 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 reverse biased.

D. The energy of the light emitted is equal to or slightly less than the energy gap of the semiconductor used.

Choose the correct answer from the options given below :

EASY
Physics>Modern Physics>Semiconductor Devices>Light Emitting Diode (LED)
The I - V characteristics of an LED is:
EASY
Physics>Modern Physics>Semiconductor Devices>Light Emitting Diode (LED)
The band gap of the semiconductor GaAs0.6P0.4 is 1.9 eV. If this material is used to make a Light Emitting Diode (LED), the colour of the emerging light will appear
EASY
Physics>Modern Physics>Semiconductor Devices>Light Emitting Diode (LED)
What is energy band gap EB for p-type and n-type semiconductor use to form a LED to produce a red light colour?
MEDIUM
Physics>Modern Physics>Semiconductor Devices>Light Emitting Diode (LED)
Why cannot we use Si and Ge in fabrication of visible LEDs ?
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Physics>Modern Physics>Semiconductor Devices>Light Emitting Diode (LED)
Write the name of any one dopped semiconductor used for making light emitting diode (LED).
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Physics>Modern Physics>Semiconductor Devices>Light Emitting Diode (LED)

LED emits light when connected in _____.

(Fill in the blank using 'forward bias' or 'reverse bias')

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Physics>Modern Physics>Semiconductor Devices>Light Emitting Diode (LED)
A light emitting diode is
MEDIUM
Physics>Modern Physics>Semiconductor Devices>Light Emitting Diode (LED)

What is the advantage of an LED bulb over filament bulb?

EASY
Physics>Modern Physics>Semiconductor Devices>Light Emitting Diode (LED)
What is LED? Mention two of its applications.
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Physics>Modern Physics>Semiconductor Devices>Light Emitting Diode (LED)
Identify the incorrect statement:
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Physics>Modern Physics>Semiconductor Devices>Light Emitting Diode (LED)
LED is constructed from Ga-As-P semiconducting material. The energy gap of this LED is 1.9 eV. Calculate the wavelength of light emitted and its colour. h=6.63×10-34 J-s and c=3×108 m s-1
EASY
Physics>Modern Physics>Semiconductor Devices>Light Emitting Diode (LED)
In LED, to avoid damage to the diode .............. is used.
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Physics>Modern Physics>Semiconductor Devices>Light Emitting Diode (LED)
Which one of the following devices does not respond to the intensity of light incident on it?
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Physics>Modern Physics>Semiconductor Devices>Light Emitting Diode (LED)
Barrier potential in LED depends on the type of
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Physics>Modern Physics>Semiconductor Devices>Light Emitting Diode (LED)
Which of the following diode emits red and yellow light?
EASY
Physics>Modern Physics>Semiconductor Devices>Light Emitting Diode (LED)

Statement-1 : Light emiting diode (LED) emits spontaneous radiation.

Statement-2 : LED is forward-biased p-n junction.

EASY
Physics>Modern Physics>Semiconductor Devices>Light Emitting Diode (LED)
The IV characteristic of an LED is,
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Physics>Modern Physics>Semiconductor Devices>Light Emitting Diode (LED)
Colour of light emitted by LED depends on
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Physics>Modern Physics>Semiconductor Devices>Light Emitting Diode (LED)
In LED, intensity of emitted light