03-01-2013, 01:34 PM
MULTIPLE CHOICE
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1. If the rms current through a 10 kΩ resistor is 5 mA, the rms voltage drop across the resistor is
a. 70.7 V
b. 7.07 V
c. 5 V
d. 50 V
2. A sinusoidal voltage is applied across a capacitor. When the frequency of the voltage is increased, the current
a. increases
b. decreases
c. remains constant
d. ceases
3. For a certain load, the real power is 100 W and the reactive power is 100 VAR. The apparent power is
a. 200 VA
b. 100 VA
c. 141.4 VA
d. 141.4 W
4. When the frequency of the source voltage is increased, the impedance of a parallel RC circuit
a. increases
b. decreases
c. does not change
5. An inductor, a resistor, and a switch are connected in series to a 12 V battery. At the instant the switch is closed, the inductor voltage
a. 0 V
b. 12 V
c. 6 V
d. 4 V
6. Which of the following power factors results in the least energy conversion to heat in an RL circuit?
a. 1
b. 0.9
c. 0.5
d. 0.1
7. When the resistor voltage in a series RL circuit becomes greater than the inductor voltage, the phase angle
a. increases
b. decreases
c. is not affected
8 . The phase angle of a series RLC circuit at resonance is
a. -90o
b. 90o
c. 0o
d. dependent on the reactance
9. If the value of C in a series RLC circuit is increased, the resonant frequency
a. is not affected
b. increases
c. remains the same
d. decreases
10. A certain transformer has 500 turns in the primary winding and 2500 turns in the secondary winding. The turns ratio is
a. 0.2
b. 2.5
c. 5
d. 0.5
11. When the turns ratio of a transformer is 0.5 and the primary AC voltage is 100 V, the secondary voltage is
a. 200 V
b. 50 V
c. 10 V
d. 100 V
12. If the β of a certain transistor operating in the linear region is 30 and the base current is 1 mA, the collector current is
a. 0.033 mA
b. 1 mA
c. 30 mA
13. When an n-type MOSFET is biased for conduction, the gate is
a. positive with respect to the source
b. negative with respect to the source
c. positive with respect to the drain
d. as the same voltage as the drain
14. The largest theoretical voltage gain obtainable with a common-collector amplifier is
a. 100
b. 10
c. 1
d. dependent of β
15. The output signal of a common-emitter amplifier is always
a. in phase with the input signal
b. out of phase with the input signal
c. larger than the input signal
d. equal to the input signal