Standing-wave vibrations are set up in a crystal wine glass with four nodes and four antinodes equally spaced around the 2.80-cm radius of the rim. If the resonant frequency of the glass is 8.50 kHz, what is the speed of the transverse waves moving around the glass?
a. 1 500 m/s
b. 748 m/s
c. 374 m/s
d. 238 m/s
[Ques. 2] In a circuit made up of inductor L, resistance R, ammeter, battery and switch in series, the current is greatest at which of the following times, as measured after the switch is closed?
a. zero
b. one time constant
c. at a time t = L/R
d. ten time constants
[Ques. 3] An astronaut sets up a pendulum on the Moon, where the acceleration due to gravity is 1/6 that of Earth. If she finds that she must push the pendulum with a frequency of 0.10 Hz to maintain a swinging motion, what is the length of the pendulum?
a. 4.1 m
b. 1.6 m
c. 99 m
d. 7.8 m
[Ques. 4] The current in a coil with a self-inductance of 2.4 mH increases from 0 to 2.66 A in a tenth of a second. What is the induced emf in the coil?
a. 64 mV
b. 6.4 mV
c. 1 700 mV
d. 5.1 V
e. 130 mV
[Ques. 5] A child sits on a swing supported by ropes of length 2.0 m. With what frequency will she need to apply the driving force to maintain swinging?
a. 0.35 Hz
b. 0.70 Hz
c. 1.7 Hz
d. 2.8 Hz
e. 5.4 Hz
[Ques. 6] By what factor is the self-inductance of an air solenoid changed if only its cross-sectional area, A, multiplied by eight?
a. 1/8
b. 8
c. 24
d. 64
e. 1/64
[Ques. 7] The lower A on a piano has a frequency of 30.0 Hz. If the tension in the 2.00-m-long string is 316 N and one-half wavelength occupies the string, what is the mass of the string?
a. 61.4 g
b. 21.9 g
c. 17.6 g
d. 43.9 g
e. 91.1 g
[Ques. 8] The self-inductance of a solenoid increases under which of the following conditions?
a. Only the solenoid length is increased.
b. Only the cross sectional area is decreased.
c. Only the number of coils per unit length is decreased.
d. Only the number of coils is increased.
[Ques. 9] 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. 10] A circular loop (area = 0.20 m2) turns in a uniform magnetic field with B = 0.13 T. At an instant when the angle between the magnetic field and the normal to the plane of the loop is rads and is decreasing at the rate of 0.50 rad/s, what is the magnitude of the emf induced in the loop?
a. zero
b. 13 mV
c. 26 mV
d. 20 mV
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