57. If the power rating of a transistor is 1 W and collector current is 100 mA, then maximum allowable collector voltage is
A. 1 V
B. 100 V
C.20 V
D. 10 V

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58. When no signal is applied, the approximate collector efficiency of class A power amplifier is
A.10%
B.0%
C.25%
D.50%

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59. What will be the collector efficiency of a power amplifier having zero signal power dissipation of 5 watts and a.c. power output of 2 watts?
A.20%
B.80%
C.40%
D.50%

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60. The output signal voltage and current of a power amplifier are 5 V and 200 mA;the values being r.m.s. What is the power output?
A. 1 W
B. 2 W
C. 4 W
D. none of the above

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61. The maximum a.c. power output from a class A power amplifier is 10 W. What should be the minimum power rating of the transistor used?
A. 10 W
B. 15 W
C. 5 W
D. 20 W

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62. For the same a.c. power output as above, what should be the minimum power rating of transistor for class B Operation?
A. 10 W
B. 4 W
C. 8 W
D. none of the above

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63. The push-pull circuit operation.
A. class A
B. class C
C. class B
D. class AB

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