In a junction diode, an equilibrium condition occurs when ____________

Optical amplification through stimulated emission

In a junction diode, an equilibrium condition occurs when

Optical amplification through stimulated emission

‚âà√≠‚àö√Üngreater than ‚âà√≠‚àö√Üp

‚âà√≠‚àö√Ünsmaller than ‚âà√≠‚àö√Üp

Optical amplification through stimulated emission

The excess density of electrons ‚âà√≠‚àö√Ünand holes ‚âà√≠‚àö√Üpin an LED is$

‚âà√≠‚àö√Üpmore than ‚âà√≠‚àö√Ün

‚âà√≠‚àö√Ün more than ‚âà√≠‚àö√Üp

The absence of _______________ in LEDs limits the internal quantum efficiency.

Optical amplification through spontaneous emission

Optical amplification through stimulated emission

Optical amplification through spontaneous emission

26 + Mcqs in Led Power Efficiency in Optical Communication Page 1 McqOptions

1.	If a particular optical power is coupled from an incoherent LED into a low-NA fiber, the device must exhibit very high radiance.
A.	True
B.	False
Answer» B. False

Discussion

2.	Determine coupling efficiency into the fiber when GaAs LED is in close proximity to fiber core having numerical aperture of 0.3.
A.	0.9
B.	0.3
C.	0.6
D.	0.12
Answer» B. 0.3

Discussion

3.	In a GaAs LED, compute the loss relative to internally generated optical power in the fiber when there is small air gap between LED and fiber core. (Fiber coupled = 5.5 * 10-4Pint)
A.	34 dB
B.	32.59 dB
C.	42 dB
D.	33.1 dB
Answer» C. 42 dB

Discussion

4.	For a GaAs LED, the coupling efficiency is 0.05. Compute the optical loss in decibels.
A.	12.3 dB
B.	14 dB
C.	13.01 dB
D.	14.6 dB
Answer» D. 14.6 dB

Discussion

5.	A planar LED is fabricated from GaAs is having a optical power emitted is 0.018% of optical power generated internally which is 0.018% of optical power generated internally which is 0.6 P. Determine external power efficiency.
A.	0.18%
B.	0.32%
C.	0.65%
D.	0.9%
Answer» E.

Discussion

6.	A planar LED fabricated from GaAs has a refractive index of 2.5. Compute the optical power emitted when transmission factor is 0.68.
A.	3.4 %
B.	1.23 %
C.	2.72 %
D.	3.62 %
Answer» D. 3.62 %

Discussion

7.	The Lambertian intensity distribution __________ the external power efficiency by some percent.
A.	Reduces
B.	Does not affects
C.	Increases
D.	Have a negligible effect
Answer» B. Does not affects

Discussion

8.	Compute power internally generated within a double-heterojunction LED if it has internal quantum efficiency of 64.5 % and drive current of 40 mA with a peak emission wavelength of 0.82 μm.
A.	0.09
B.	0.039
C.	0.04
D.	0.06
Answer» C. 0.04

Discussion

9.	In a junction diode, an equilibrium condition occurs when ____________
A.	Δngreater than Δp
B.	Δnsmaller than Δp
C.	Constant current flow
D.	Optical amplification through stimulated emission
Answer» D. Optical amplification through stimulated emission

Discussion

10.	The carrier recombination lifetime becomes majority or injected carrier lifetime.
A.	True
B.	False
Answer» C.

Discussion

11.	The excess density of electrons Δnand holes Δpin an LED is ____________
A.	Equal
B.	Δpmore than Δn
C.	Δn more than Δp
D.	Does not affects the LED
Answer» B. Δpmore than Δn

Discussion

12.	THE_LAMBERTIAN_INTENSITY_DISTRIBUTION____________THE_EXTERNAL_POWER_EFFICIENCY_BY_SOME_PERCENT.?$
A.	Reduces
B.	Does not affects
C.	Increases
D.	Have a negligible effect
Answer» B. Does not affects

Discussion

13.	A planar LED is fabricated from GaAs is having a optical power emitted is 0.018% of optical power generated internally which is 0.018% of optical power generated internally which is 0.6 P. Determine external power efficiency.$
A.	0.18%
B.	0.32%
C.	0.65%
D.	0.9%
Answer» E.

Discussion

14.	A_planar_LED_fabricated_from_GaAs_has_a_refractive_index_of_2.5._Compute_the_optical_power_emitted_when_transmission_factor_is_0.68.$
A.	3.4 %
B.	1.23 %
C.	2.72 %
D.	3.62 %
Answer» D. 3.62 %

Discussion

15.	If a particular optical power is coupled from an incoherent LED into a low-NA fiber, the device must exhibit very high radiance . State whether the given statement is true or false.
A.	True
B.	False
Answer» B. False

Discussion

16.	Determine coupling efficiency into the fiber when GaAs LED is in close proximity to fiber core having numerical aperture of 0.3
A.	0.9
B.	0.3
C.	0.6
D.	0.12
Answer» B. 0.3

Discussion

17.	In a GaAs LED, compute the loss relative to internally generated optical power in the fiber when there is small air gap between LED and fiber core. (Fiber coupled = 5.5 * 10^-4P_int)
A.	34 dB
B.	32.59 dB
C.	42 dB
D.	33.1 dB
Answer» C. 42 dB

Discussion

18.	For_a_GaAs_LED,_the_coupling_efficiency_is_0.05._Compute_the_optical_loss_in_decibels.
A.	12.3 dB
B.	14 dB
C.	13.01 dB
D.	14.6 dB
Answer» D. 14.6 dB

Discussion

19.	Compute power internally generated within a double-heterojunction LED if it has internal quantum efficiency of 64.5 % and drive current of 40 mA with a peak emission wavelength of 0.82 ‚âà√≠¬¨‚à´m?#
A.	0.09
B.	0.039
C.	0.04
D.	0.06
Answer» C. 0.04

Discussion

20.	Determine the internal quantum efficiency generated within a device when it has a radiative recombination lifetime of 80 ns and total carrier recombination lifetime of 40 ns.
A.	20 %
B.	80 %
C.	30 %
D.	40 %
Answer» C. 30 %

Discussion

21.	Determine the total carrier recombination lifetime of a double heterojunction LED where the radioactive and nonradioactive recombination lifetime of minority carriers in active region are 70 ns and 100 ns respectively.
A.	41.17 ns
B.	35 ns
C.	40 ns
D.	37.5 ns
Answer» B. 35 ns

Discussion

22.	In a junction diode, an equilibrium condition occurs when
A.	‚âà√≠‚àö√Üngreater than ‚âà√≠‚àö√Üp
B.	‚âà√≠‚àö√Ünsmaller than ‚âà√≠‚àö√Üp
C.	Constant current flow
D.	Optical amplification through stimulated emission
Answer» D. Optical amplification through stimulated emission

Discussion

23.	The carrier recombination lifetime becomes majority or injected carrier lifetime. State whether the given statement is true or false.
A.	True
B.	False
Answer» C.

Discussion

24.	The hole concentration in extrinsic materials is _________ electron concentration.
A.	much greater than
B.	lesser than
C.	equal to
D.	negligible difference with
Answer» B. lesser than

Discussion

25.	The excess density of electrons ‚âà√≠‚àö√Ünand holes ‚âà√≠‚àö√Üpin an LED is$
A.	Equal
B.	‚âà√≠‚àö√Üpmore than ‚âà√≠‚àö√Ün
C.	‚âà√≠‚àö√Ün more than ‚âà√≠‚àö√Üp
D.	Does not affects the LED
Answer» B. ‚âà√≠‚àö√Üpmore than ‚âà√≠‚àö√Ün

Discussion

26.	The absence of _______________ in LEDs limits the internal quantum efficiency.
A.	Proper semiconductor
B.	Adequate power supply
C.	Optical amplification through stimulated emission
D.	Optical amplification through spontaneous emission
Answer» D. Optical amplification through spontaneous emission

Discussion

Explore topic-wise MCQs in Optical Communication.

If a particular optical power is coupled from an incoherent LED into a low-NA fiber, the device must exhibit very high radiance.

Determine coupling efficiency into the fiber when GaAs LED is in close proximity to fiber core having numerical aperture of 0.3.

In a GaAs LED, compute the loss relative to internally generated optical power in the fiber when there is small air gap between LED and fiber core. (Fiber coupled = 5.5 * 10-4Pint)

For a GaAs LED, the coupling efficiency is 0.05. Compute the optical loss in decibels.

A planar LED is fabricated from GaAs is having a optical power emitted is 0.018% of optical power generated internally which is 0.018% of optical power generated internally which is 0.6 P. Determine external power efficiency.

A planar LED fabricated from GaAs has a refractive index of 2.5. Compute the optical power emitted when transmission factor is 0.68.

The Lambertian intensity distribution __________ the external power efficiency by some percent.

Compute power internally generated within a double-heterojunction LED if it has internal quantum efficiency of 64.5 % and drive current of 40 mA with a peak emission wavelength of 0.82 μm.

In a junction diode, an equilibrium condition occurs when ____________

The carrier recombination lifetime becomes majority or injected carrier lifetime.

The excess density of electrons Δnand holes Δpin an LED is ____________

THE_LAMBERTIAN_INTENSITY_DISTRIBUTION____________THE_EXTERNAL_POWER_EFFICIENCY_BY_SOME_PERCENT.?$

A planar LED is fabricated from GaAs is having a optical power emitted is 0.018% of optical power generated internally which is 0.018% of optical power generated internally which is 0.6 P. Determine external power efficiency.$

A_planar_LED_fabricated_from_GaAs_has_a_refractive_index_of_2.5._Compute_the_optical_power_emitted_when_transmission_factor_is_0.68.$

If a particular optical power is coupled from an incoherent LED into a low-NA fiber, the device must exhibit very high radiance . State whether the given statement is true or false.

Determine coupling efficiency into the fiber when GaAs LED is in close proximity to fiber core having numerical aperture of 0.3

In a GaAs LED, compute the loss relative to internally generated optical power in the fiber when there is small air gap between LED and fiber core. (Fiber coupled = 5.5 * 10-4Pint)

For_a_GaAs_LED,_the_coupling_efficiency_is_0.05._Compute_the_optical_loss_in_decibels.

Compute power internally generated within a double-heterojunction LED if it has internal quantum efficiency of 64.5 % and drive current of 40 mA with a peak emission wavelength of 0.82 ‚âà√≠¬¨‚à´m?#

Determine the internal quantum efficiency generated within a device when it has a radiative recombination lifetime of 80 ns and total carrier recombination lifetime of 40 ns.

Determine the total carrier recombination lifetime of a double heterojunction LED where the radioactive and nonradioactive recombination lifetime of minority carriers in active region are 70 ns and 100 ns respectively.

In a junction diode, an equilibrium condition occurs when

The carrier recombination lifetime becomes majority or injected carrier lifetime. State whether the given statement is true or false.

The hole concentration in extrinsic materials is _________ electron concentration.

The excess density of electrons ‚âà√≠‚àö√Ünand holes ‚âà√≠‚àö√Üpin an LED is$

The absence of _______________ in LEDs limits the internal quantum efficiency.

In a GaAs LED, compute the loss relative to internally generated optical power in the fiber when there is small air gap between LED and fiber core. (Fiber coupled = 5.5 * 10^-4P_int)