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Free download in PDF LED Objective Type Questions and Answers for competitive exams. These short objective type questions with answers are very important for Board exams as well as competitive exams. These short solved questions or quizzes are provided by Gkseries.
(21)
The current in a circuit is 45mA. This is:
[A]
0.045Amp
[B]
0.00045A
[C]
0.0045A
[D]
0.45A
(22)
To obtain a higher value of resistance, resistors are connected in:
[A]
Reverse
[B]
Forward
[C]
Parallel
[D]
Series
(23)
A 10k resistor in parallel with 10k produces:
[A]
10k
[B]
5k
[C]
20k
[D]
Cannot be determined
(24)
What does LED stand for?
[A]
Light Emitting Display
[B]
Low Energy Display
[C]
Light Emitting Diode
[D]
Light Emitting Detector
Answer: Light Emitting Diode
(25)
A 100n capacitor in parallel with 10n produces:
[A]
90n
[B]
100n
[C]
110n
[D]
Cannot be determined
(26)
The InGaAsP is emitting LEDs are realized in terms of restricted
[A]
Length strip geometry
[B]
Radiance
[C]
Current spreading
[D]
Coupled optical power
Answer: Length strip geometry
(27)
The active layer of E-LED is heavily doped with
[A]
Zn
[B]
Eu
[C]
Cu
[D]
Sn
(28)
Connecting a lead from the negative to the positive of a battery will produce:
[A]
A high resistance circuit
[B]
A short circuit
[C]
A low current path
[D]
An open circuit
(29)
What is the approximate characteristic voltage that develops across a red LED?
[A]
1.7v
[B]
3.4v
[C]
0.6v
[D]
All the above
(30)
If two resistors are placed in series, is the final resistance:
[A]
Higher
[B]
Lower
[C]
The same
[D]
Cannot be determined
31
If the voltage on the base of a transistor increases, does it:
[A]
Turn on
[B]
Turn off
[C]
Not enough information
[D]
Remain the same
Answer: Not enough information
32
If a small value of capacitance is connected in parallel with a large value, the combined capacitance will be:
[A]
The same
[B]
Higher
[C]
Lower
[D]
All above
33
Which is not a "common" value of resistance?
[A]
2k7
[B]
1M8
[C]
330R
[D]
4k4
34
A resistor with colour bands: red-red-red-gold, has the value:
[A]
22k 5%
[B]
2k2 5%
[C]
220R 5%
[D]
22R 5%
35
Mesa structured SLEDs are used
[A]
To reduce radiance
[B]
To increase radiance
[C]
To reduce current spreading
[D]
To increase current spreading
Answer: To reduce current spreading
36
The overall power conversion efficiency of electrical lens coupled LED is 0.8% and power applied 0.0375 V. Determine optical power launched into fiber
[A]
0.03
[B]
0.05
[C]
0.3
[D]
All of the above
37
Determine the overall power conversion efficiency of lens coupled SLED having forward current of 20 mA and forward voltage of 2 V with 170 μWof optical power launched into multimode step index fiber.
[A]
1.256*10-5
[B]
4.417*102
[C]
4.25*10-3
[D]
2.14*10-3
38
Internal absorption in DH surface emitter Burros type LEDs is
[A]
Cannot be determined
[B]
Negligible
[C]
High
[D]
Very low
39
DH surface emitter generally give
[A]
More coupled optical power
[B]
Less coupled optical power
[C]
Low current densities
[D]
Low radiance emission into-fiber
Answer: More coupled optical power
40
In a multimode fiber, much of light coupled in the fiber from an LED is
[A]
Increased
[B]
Reduced
[C]
Lost
[D]
Unaffected
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