A transformer has a primary voltage of 120 V rms and a secondary voltage of 25 V rms. If the secondary current is 1A rms, what is the primary current?
A. 7.8 mA
B. 208 mA
C. 200 mA
D. 300 mA
E. None of the above
Answer: Option B
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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