A 60.0-Hz AC generator with a peak voltage of 110 V drives a series RC circuit with R = 10.0 and C = 300 F. The peak current in the circuit is
a. 8.24 A.
b. 8.84 A.
c. 11.0 A.
d. 12.4 A.
e. 23.5 A.
[Ques. 2] The average power input to a series alternating current circuit is minimum when
a. there are only a resistor and capacitor in the circuit.
b. there are only a resistor and inductor in the circuit.
c. there is only a resistor in the circuit.
d. XL = XC and the circuit contains a resistor, an inductor and a capacitor.
e. there is only a capacitor in the circuit.
[Ques. 3] Whenever the alternating current frequency in a series RLC circuit is halved,
a. the inductive reactance is doubled and the capacitive reactance is halved.
b. the inductive reactance is doubled and the capacitive reactance is doubled.
c. the inductive reactance is halved and the capacitive reactance is halved.
d. the inductive reactance is halved and the capacitive reactance is doubled.
e. the reactance of the circuit remains the same.
[Ques. 4] In a typical transmission line, the current I is very small and the voltage V is very large. A unit length of line has resistance R. For a power line that supplies power to 10,000 households, we can conclude that
a. IV = I 2R.
b. I = V/R.
c. IV < I 2R.
d. IV > I 2R.
e. I 2R = 0.
[Ques. 5] An ideal step-down transformer has 200 primary turns and 50 secondary turns. If 440 volts (rms) is placed across the primary, what is the current in the secondary when the load resistance is 7.00 ohms?
a. 3.6 A (rms)
b. 7.3 A (rms)
c. 11.4 A (rms)
d. 15.7 A (rms)
e. 12.4 A (rms)
[Ques. 6] A primary current of 6.0 A exists in an ideal iron-core transformer at a primary voltage of 100 volts. If the current in the secondary is 0.75 A, calculate the output voltage.
a. 12.5 V
b. 40 V
c. 400 V
d. 800 V
e. 200 V
[Ques. 7] A step-up transformer has an input voltage of 110 V (rms). There are 100 turns on the primary and 1500 on the secondary. What is the output voltage?
a. 1600 V (max)
b. 1650 V (rms)
c. 3260 V (max)
d. 165 kV (rms)
e. 7.3 V (rms)
[Ques. 8] The primary winding of an electric train transformer has 400 turns and the secondary has 50 . If the input voltage is 120 V (rms) what is the output voltage?
a. 15 V (rms)
b. 30 V (rms)
c. 60 V (rms)
d. 2.4 V (rms)
e. 960 V (rms)
[Ques. 9] A transformer is to be designed to increase the 30 kV rms output of a generator to the transmission-line voltage of 345 kV rms. If the primary winding has 80 turns, how many turns must the secondary have?
a. 6
b. 70
c. 920
d. 9200
e. 12
[Ques. 10] A series RLC circuit has an impedance of 120 and a resistance of 64 . What average power is delivered to this circuit when Vrms = 90 volts?
a. 36 W
b. 100 W
c. 192 W
d. 360 W
e. 12 W
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