In an AC series circuit, the voltage in the inductor differs in phase with the voltage in the capacitor by what angle?
a. 180
c. 90
b. zero
d. 45
[Ques. 2] A note is being played on a string on a guitar. The string is then pushed to the side while still in contact with the same fret. What happens to the frequency of the note then played compared to the original note?
a. It is the same note since the same fret is being used. b. It is at higher frequency than the original note.
c. It is at lower frequency than the original note.
d. It can be either higher of lower frequency depending on whether the original note was above or below middle C.
[Ques. 3] In the inductor of a 60-Hz AC series circuit, the peak voltage precedes the peak current in each cycle by what time interval?
a. 2.1 10-3 s
c. 4.2 10-3 s
b. 8.3 10-3 s
d. 1.7 10-3 s
[Ques. 4] A C note (f = 128 Hz) is sounded on a piano. If the length of the piano wire is 1.00 m and its mass density is 5.00 g/m, what is the tension in the wire?
a. 84 N
c. 655 N
b. 328 N
d. 1310 N
[Ques. 5] In a capacitor in an AC circuit, the voltage:
a. lags the current by 90.
b. may lead or lag the current depending on the frequency.
c. leads the current by 90.
d. is in phase with 70.7 of the current.
[Ques. 6] I stretch a rubber band and plunk it to make it vibrate in its fundamental frequency. I then stretch it to twice its length and make it vibrate in the fundamental frequency once again. This rubber band is made so that doubling its length doubles the tension and reduces the mass per unit length by a factor of 2 . The new frequency will be related to the old by a factor of:
a. 4.0.
c. 1.4.
b. 2.0.
d. 1.0.
[Ques. 7] When a 50-mF capacitor is attached to an AC source, its capacitive reactance is 60 W. If instead a 200-mF capacitor is attached to the same source, what will be its capacitive reactance?
a. 80 W
c. 30 W
b. 15 W
d. 120 W
[Ques. 8] For a standing wave on a string, the wavelength must equal:
a. the distance between adjacent nodes.
b. the distance between adjacent antinodes.
c. twice the distance between adjacent nodes.
d. the distance between supports.
[Ques. 9] A 17.0-mF capacitor is connected to an AC source with an rms voltage of 120 V and a frequency of 60.0 Hz. What is the rms current in the capacitor?
a. 1.41 A
c. 0 A
b. 0.543 A
d. 0.769 A
[Ques. 10] A standing wave is set up in a 2.0-m string fixed at both ends. The string vibrates in 3 distinct segments when driven by a 120-Hz source. In how many distinct standing wave segments will the string vibrate if the tension is increased by a factor of 4?
a. 3
c. 9
b. 6
d. No standing wave pattern occurs.
Quick Reply
