Exam 26: AC Electricity

A 120-V rms voltage at 1.0 kHz is applied to a 2.0-mH inductor, a 4.0-μF capacitor and a resistor. If the rms value of the current in this circuit is 0.40 A, what is the value of the resistor?

The primary of an ideal transformer has 100 turns and its secondary has 200 turns. If the input voltage to the primary is 100 V, we can expect the output voltage of the secondary to be

A series circuit consists of a 0.440-H inductor, a 380.0-Ω resistor, a 5.70-μF capacitor, and an ac voltage source of amplitude $250.0 \mathrm {~V}$ Find the rms voltage across the capacitor when the circuit operates at resonance.

The reactance of a capacitor is $4.0 \mathrm { k } \Omega$ at a frequency of $0.60 \mathrm { kHz }$ What is the capacitance?

The primary coil of an ideal transformer has 100 turns and its secondary coil has 400 turns. If the ac voltage applied to the primary coil is 120 V, what voltage is present in its secondary coil?

As shown in the figure, an ac source whose rms voltage is 80 V is in series with a 100-Ω resistor and a capacitor whose reactance is 200 Ω at the frequency of the source. What is the rms voltage across the capacitor?

An ideal transformer with 120 turns in its secondary supplies 12 V at 220 mA to a toy train. The primary is connected across a 120-V wall outlet. (a) How many turns are in the primary? (b) What is the primary current? (c) What power is delivered by the wall outlet?

At what frequency will the inductive reactance of a 44-mH inductor be equal to the capacitive reactance of a 27-pF capacitor?

A simple ac circuit consists of an inductor connected across the terminals of an ac power source. If the frequency of the ac source is decreased by a factor of four, what happens to the reactance of the inductor?

What is the inductive reactance of a 2.50-mH coil at 1000 Hz?

An ideal transformer consists of a 500-turn primary coil and a 2000-turn secondary coil. If the current in the secondary is 3.0 A, what is the current in the primary?

What is the reactance of a 20-mH inductor at a frequency of 60 Hz?

An ideal transformer steps down 120 V to 12. V and the 2630.-turn secondary supplies 12. A. (a) Determine the current in the primary. (b) Determine the turns ratio. (c) What is the ratio of output power to input power?

A 150-W lamp is placed into a 120-V ac outlet. What is the peak current?

A pure inductor is connected to an ac power supply. In this circuit, the current

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 1000/π Hz. What is the rms voltage across the inductor?

The secondary coil of an ideal neon sign transformer provides 7500 V at 10.0 mA. The primary coil operates on 120 V. What current does the primary draw?

The potential applied to a 20-Ω resistor is (60 V) cos(33t). What is the average power consumed in the resistor?

At what frequency does a 10-μF capacitor have a reactance of 0.12 kΩ?

The primary of an ideal transformer has 100 turns and its secondary has 200 turns. If the input current at the primary is 100 A, we can expect the output current at the secondary to be