LED Structures MCQ

Test your knowledge with important LED Structures MCQ and their applications. These MCQs are beneficial for competitive exams too. Explore 30 + more LED Structures MCQs at Bissoy

• The active layer of E-LED is heavily doped with ____________
  ক

  Zn

  খ

  Eu

  গ

  Cu

  ঘ

  Sn
• The InGaAsP is emitting LEDs are realized in terms of restricted are ____________
  ক

  Length strip geometry

  খ

  Radiance

  গ

  Current spreading

  ঘ

  Coupled optical power
• Mesa structured SLEDs are used ____________
  ক

  To reduce radiance

  খ

  To increase radiance

  গ

  To reduce current spreading

  ঘ

  To increase current spreading
• 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.
  ক

  0.03

  খ

  0.05

  গ

  0.3

  ঘ

  0.01
• 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.
  ক

  1.256*10-5

  খ

  4.417*102

  গ

  4.25*10-3

  ঘ

  2.14*10-3
• In a multimode fiber, much of light coupled in the fiber from an LED is ____________
  ক

  Increased

  খ

  Reduced

  গ

  Lost

  ঘ

  Unaffected
• Estimate optical power coupled into fiber of DH SLED having emission area of 1.96*10-5, radiance of 40 W/rcm2, numerical aperture of 0.2 and Fresnel reflection coefficient of 0.03 at index matched fiber surface.
  ক

  5.459*10-5

  খ

  1.784*10-3

  গ

  3.478*102

  ঘ

  9.551*10-5
• A DH surface emitter LED has an emission area diameter of 60μm. Determine emission area of source.
  ক

  1.534*10-6

  খ

  5.423*10-3

  গ

  3.564*10-2

  ঘ

  2.826*10-9
• DH surface emitter generally give ____________
  ক

  More coupled optical power

  খ

  Less coupled optical power

  গ

  Low current densities

  ঘ

  Low radiance emission into-fiber
• Internal absorption in DH surface emitter Burros type LEDs is ____________
  ক

  Cannot be determined

  খ

  Negligible

  গ

  High

  ঘ

  Very low
• In surface emitter LEDs, more advantage can be obtained by using ____________
  ক

  BH structures

  খ

  QC structures

  গ

  DH structures

  ঘ

  Gain-guided structure
• The techniques by Burros and Dawson in reference to homo structure device is to use an etched well in GaAs structure.
  ক

  True

  খ

  False
• As compared to planar LED structure, Dome LEDs have ______________ External power efficiency ___________ effective emission area and _____________ radiance.
  ক

  Greater, lesser, reduced

  খ

  Higher, greater, reduced

  গ

  Higher, lesser, increased

  ঘ

  Greater, greater, increased
• In optical fiber communication _____________ major types of LED structures are used.
  ক

  2

  খ

  4

  গ

  6

  ঘ

  3
• The amount of radiance in planer type of LED structures is ____________
  ক

  Low

  খ

  High

  গ

  Zero

  ঘ

  Negligible