Exam 35: Ac Circuits

A 120-V rms voltage at 60.0 Hz is applied across an inductor, a capacitor, and a resistor in series. If the peak current in this circuit is 0.8484 A, what is the impedance of this circuit?

A 25.0-mH inductor, a 2.00-μF capacitor, and a certain resistor are connected in series across an ac voltage source at 1000 Hz. If the impedance of this circuit is 200 Ω, what is the resistance of the resistor?

(a) In an ac circuit, if the peak value of the voltage is 100 V, what is the rms value of the voltage? A) 141 V B) 100 V C) 210 V D) 71 V E) 120 V (b) In an ac circuit, if the rms value of the current is 100 mA, what is the peak value of the current? A) 141 mA B) 100 mA C) 210 mA D) 71 mA E) 120 mA

An LRC series circuit has voltage supplied to it at a frequency of 13.0 kHz with a phase difference between the current and the voltage of magnitude 0.20 rad. If the circuit has a capacitance of 5.0 μF and an inductance of 0.050 H find the resistance of the circuit.

In a series LRC circuit, the frequency at which the circuit is at resonance is f₀. If you double the resistance, the inductance, the capacitance, and the voltage amplitude of the ac source, what is the new resonance frequency?

A series circuit consists of a 50-Hz ac source, a 40-Ω resistor, a 0.30-H inductor, and a 60-μF capacitor. The rms current in the circuit is measured to be 1.6 A. What is the power factor of the circuit?

An LRC ac series circuit with R = 15 Ω, L = 25 mH, and C = 30 μF, is attached to a 100-V (rms) ac power supply. The frequency of the power supply is adjusted so that the circuit is in resonance. (a) What is the rms current in the circuit? (b) What is the power dissipated by the circuit?

A series circuit has a resistance of 4.0 Ω, a reactance (due to the capacitance) of 21.0 Ω, and a reactance (due to the inductance) of 17.0 Ω. Find the impedance of the circuit.

An ac circuit is shown in the figure. The rms current in the circuit is 1.3 A. What is the peak magnetic energy in the inductance?

If the voltage amplitude across an 8.50-nF capacitor is equal to 12.0 V when the current amplitude through it is 3.33 mA, the frequency is closest to:

The phase angle of an LRC series circuit with an inductive reactance of 200 Ω, a resistor of 200 Ω and a certain capacitor at 1000 Hz is 40.0°. What is the value of the capacitance in this circuit?

A series LRC circuit consists of a 5.00-pF capacitor, a 7.25-mH inductor, a 75.0-Ω resistor, and a 50.0-V ac power source of variable frequency. At what frequency will the impedance of this circuit be equal to 75.0 Ω?

An LRC ac series circuit has R = 15 Ω, L = 25 mH, and C = 30 μF. The circuit is connected to a 120-V (rms) ac source with frequency 200 Hz. (a) What is the average power dissipated by the circuit? (b) What is the power factor for the circuit?

A series LRC circuit consists of an ac voltage source of amplitude 75.0 V and variable frequency, a 12.5-µF capacitor, a 5.00-mH inductor, and a 35.0-Ω resistor. (a) To what angular frequency should the ac source be set so that the current amplitude has its largest value? (b) Under the conditions of part (a), what is the maximum current amplitude? (c) Suppose that the voltage source is set to twice the angular frequency needed in part (a). What will be the current amplitude in this case?

A series circuit consists of ac source, a 90-Ω resistor, a 0.80-H inductor, and an 80-μF capacitor. The frequency of the source is adjusted so that the capacitive reactance is equal to twice the inductive reactance. What is the frequency of the source?

An ac circuit is shown in the figure. The rms current in the circuit is measured to be 1.8 A. What is the capacitance of the capacitor?

A series ac circuit consists of a voltage source of frequency 60 Hz and source voltage amplitude 345 volts, a 701-Ω resistor, a 1.6-μF capacitor, and an inductor of inductance L. (a) What must be the value of L for the phase angle to be zero? (b) When L has the value calculated in part (a), what is the current amplitude in the circuit?

A resistor is connected to an ideal ac power supply. (a) The phase angle between the current and voltage is A) 0 B) π/2 radians. C) -π/2 radians. D) π radians. E) 3π/4 radians. (b) The current in the resistor A) leads the voltage across the resistor by 90°. B) lags the voltage across the resistor by 90°. C) is in phase with the voltage across the resistor. D) the voltage across the resistor by 45°. E) lags the voltage across the resistor by 45°. (c) How does the average power dissipated in the resistor change as the frequency in the ac power supply decreases? A) It decreases. B) It increases. C) It does not change. D) It increases or decreases depending on the sign of the phase angle.

A series ac circuit consists of an inductor having a reactance of 80 Ω and an inductance of 190 mH, a 40-Ω resistor, a capacitor whose reactance is 100 Ω, and an ac source. The rms current in the circuit is measured to be 2.2 A. What is the rms voltage of the source?

When an LRC series circuit is at resonance, which one of the following statements about that circuit is accurate? (There may be more than one correct choice.)