Which one of the following statements most accurately reflects the nature of ac power?
A. The current in an ac circuit flows in one direction, but changes value periodically
B. The current in an ac circuit flows in one direction at a steady level
C. The current in an ac circuit changes direction periodically
D. The current in an ac circuit flows in two directions at the same time
E. None of the above
Answer: Option C
This Question Belongs to Computer Science >> Electronic Principles
In an intrinsic semiconductor, the number of free electrons
A. Equals the number of holes
B. Is less than the number of holes
C. Is greater than the number of holes
D. Impossible to say
E. None of the above
A device that converts mechanical into electrical energy is?
A. solar cell
B. thermocouple
C. chemical cell
D. generator
E. None of the above
Which one of the following kinds of materials has the lowest permeability?
A. A diamagnetic material
B. A paramagnetic material
C. A feiTomagnetic material
D. All of the above
E. None of the above
The total impedance of a parallel RLC circuit:
A. always increases as the applied frequency increases
B. is equal to the sum of the values of resistance, inductive reactance and capacitive reactance
C. always decreases as the applied frequency increases
D. is maximum at the resonant frequency
E. None of the above
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