Exam 26: AC Electricity

A series circuit contains an 80-μF capacitor, a 0.020-H inductor, and a switch. The resistance of the circuit is negligible. Initially, the switch is open, the capacitor voltage is 50 V, and the current in the inductor is zero. At time t = 0 s, the switch is closed. How long after closing the switch does the magnetic energy in the inductor first reach its maximum value?

A 120-mH inductor is in series with a 20-Ω resistor and a variable capacitor that can range from 0.110 μF to 0.400 μF. (a) What is the range of possible resonance frequencies? (b) If the power supply is a 24-V rms source, what rms current flows at resonance?

A 120-V rms voltage is applied across a 6.0-μF capacitor. If the frequency of the generator is 60 Hz, what is the rms value of the current in the circuit?

A simple ac circuit is composed of a capacitor connected across the terminals of an ac power source. If the frequency of the source is doubled, what happens to the reactance of the capacitor?

A current of 2.0 A in the 100-turn primary of an ideal transformer causes 14 A to flow in the secondary. How many turns are in the secondary?

The current through a 50-Ω resistor is I = (0.80 A) sin(240t), where t is measured in seconds. How much power on average is dissipated in the resistor?

The inductor in a radio receiver carries a current of amplitude 0.200 A when an ac voltage of amplitude 2.40 V is across it at a frequency of 1400 Hz. What is the value of the inductance?

The capacitive reactance of a 44-μF capacitor in an ac circuit is 6.0 × $10^2$ Ω. What is the frequency of the applied signal?

What capacitance will have the same reactance as a 100-mH inductance of both of them are in a 120-V 60-Hz circuit?

A generator produces 60 A of current at 120 V. The voltage is usually stepped up to 4500 V by an ideal transformer and transmitted through a power line of total resistance 1.0 Ω. Find the number of turns in the secondary if the primary has 200 turns.

What is the phase angle between the voltages of the inductor and capacitor in a RLC series circuit?

A series circuit has a 100-Ω resistor, a 0.100-μF capacitor, and a 2.00-mH inductor connected across a 120-V rms ac source operating at resonant frequency. What is the rms value of the voltage across the capacitor?

At what frequency is the reactance of a 20.0-mH inductor equal to 120 Ω?

A 100-W light bulb is powered by 120 V ac 60.0-Hz household connection. Determine the rms current and the current amplitude.

A series ac circuit has a resonance frequency of 9.0 kHz. If the inductor in the circuit has a value of 2.0 H, and the resistance is 75 Ω, what is the capacitance of the circuit?

The potential applied to a 20-Ω resistor is v = (60 V) cos(33t). What is the rms current through this resistor?

A 120-V rms voltage is applied across a 6.0-μF capacitor and a series combination of a 100-Ω resistor. If the frequency of the power source is 60 Hz, what is the rms value of the current in the circuit?

As the frequency of the ac voltage across an inductor approaches zero, the inductive reactance of that coil

A 120-V rms voltage at 2000 Hz is applied to a 6.0-mH inductor, a 2.0-μF capacitor, and a 200-Ω resistor. What is the rms value of the current in this circuit?

The current through a 50-Ω resistor is I = (0.80 A) sin(240t), where t is measured in seconds. What is the rms current?