The rms current is equal to the direct current that:
a. produces the same average voltage across a resistor as in an AC circuit.
b. provides the same average current in a resistor as in an AC circuit.
c. results in the same peak power in a resistor as in an AC circuit.
d. dissipates an equal amount of energy in a resistor at the same rate as in an AC circuit.
[Ques. 2] If I double the mass per unit length of guitar string, its natural frequency changes by what factor?
a. 2.0
c. 1.0
b. 1.4
d. 0.71
[Ques. 3] An AC voltage source, with a peak output of 200 V, is connected to a 25-W resistor. What is the rate of energy dissipated due to heat in the resistor?
a. 566 W
c. 800 W
b. 400 W
d. 200 W
[Ques. 4] Tripling the tension in a guitar string will change its natural frequency by what factor?
a. 3
c. 31/2
b. 31/2
d. 1.5
[Ques. 5] An AC voltage source, with a peak output of 200 V, is connected to a 25-W resistor. What is the effective (or rms) current in the circuit?
a. 2.8 A
c. 4.0 A
b. 5.7 A
d. 2.0 A
[Ques. 6] If the tension on a guitar string is increased by a factor of 2, the fundamental frequency at which it vibrates is changed by what factor?
a. 0.5
c. 21/2
b. 21/2
d. 2
[Ques. 7] The rate of heat dissipation in an AC circuit with resistance, R, and effective current, Irms, is given by which of the following?
a. (Irms)2R
c. 2.0 (Irms)2R
b. 4.0 (Irms)2R
d. 0.5 (Irms)2R
[Ques. 8] A string with fixed ends is made to go into standing wave patterns. At a given tension, the lowest frequency for which such a pattern exists is 150 Hz. Which of the following frequencies would also cause a standing wave pattern in this case?
a. 250 Hz
b. 500 Hz
c. 750 Hz
d. All of the above frequencies will cause a standing wave pattern in this case.
[Ques. 9] In an AC series circuit, the current in a pure resistor differs in phase with the applied voltage by what angle?
a. 180
c. 90
b. zero
d. 45
[Ques. 10] A string of length L with fixed ends is made to go into standing wave patterns. What is the longest wavelength associated with all possible standing wave patterns in this situation?
a. L/4
c. L
b. L/2
d. 2L
Quick Reply
