Which one of the following phrases best describes residual magnetism?
A. Magnetism that remains in the core of an electromagnet after the current through the coil is turned off
B. The force of attraction between the poles of a permanent and temporary magnetic field
C. The amount of magnetic flux that is not confined to the core material of an electromagnet
D. The circular magnetic field that surrounds a conductor carrying a current
E. None of the above
Answer: Option A
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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