Which quantity controls the effectiveness of LED in emitting light?

A)
Temperature
B)
Current
C)
Applied voltage
D)
Extent of doping

Correct Answer : Option (A) :   Temperature

Recently Updated in Electronic Devices and Circuits Questions
The kinetic energy of photoelectrons emitted by a photo sensitive surface depends on
A)
angle of incidence of radiation
B)
surface conditions of the surface
C)
intensity of the incident radiation
D)
wavelength of the incident radiation

Correct Answer :   wavelength of the incident radiation

For radiating ultraviolet rays, LEDs use
A)
gallium arsenide
B)
zinc sulphide
C)
gallium phosphide
D)
None of the above

Correct Answer :   zinc sulphide

For an P-N-P transistor in normal operation its junction are biased as
A)
emitter base : reverse, collector base : reverse
B)
emitter base : reverse, collector base : forward
C)
emitter base : forward, collector base : forward
D)
emitter base : forward, collector base : reverse

Correct Answer :   emitter base : forward, collector base : reverse

ECE MCQ's

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