Light Emitting Diode or LED objective questions and answers

26. The colour of emitted light from LED depends on

   A.Construction of LED, that is physical dimensions

   B.Number of available carriers

   C.Type of semiconductor material used

   D.Number of recombinations taking place

27. The advantage of LED is

   A.Long life

   B.Fast on-off switching

   C.Low operating voltage

   D.All of the above

28. The typical value of power consumption of LED is

   A.Around 10 mW

   B.In between 15 mW and 20 mW

   C.In between 30 mW and 40 mW

   D.In between 35 mW and 50 mW

29. When forward biased, LED emits light because of

   A.Recombination of carriers

   B.Light generated in breaking the covalent bonds

   C.Light produced by collisions

   D.All of the above reasons

30. The LEDs made with GaAs emit light in the

   A.Yellow region

   B.Infrared region

   C.Orange region

   D.Red visible region

< 1 2 3 4 5 6 7 8 9 10 Next>