85. The best value of rectification efficiency for a full wave (unfiltered) rectifier could be around
A. 50 percent
B. 65 percent
C. 80 percent
D. 95 percent

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86. The best value of rectification efficienty for a half wave rectifier could be around
A. 40 percent
B. 55 percent
C. 80 percent
D. 95 percent

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87. For a half wave rectified sine wave the ripple factor is
A.1.65
B.1.45
C.1.21
D.1

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88. The effect used in LED (Light Emitting Diode) is
A. radiative combination
B. formation of phonons
C. energy transfer from one electron to another when excited electron reverts from conduction band to valence band
D. formation of light emission

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89. In LED, light is emitted because
A. light falls on LED
B. diode emits light when heated
C. recombination of charges takes place
D. any of the above

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90. Which of the following is an active device?
A. Electric bulb
B. Transformer
C. SCR
D. Loudspeaker

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91. Which of the following is a passive component?
A. Vacuum tube devices
B. Capacitors
C. Semiconductor devices
D. All of the above

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