Exam 21: Alternating-Current Circuits

In the U.K. the power companies supply an rms voltage of 240 V to most home outlets. If you were to try and use your standard U.S.-rated 1200-W at 120-V) hair dryer in the U.K. without using a transformer, what would be the average power supplied to the hair dryer?

As the frequency in this simple AC circuit increases, the rms current through the resistor

A 5-μF capacitor is charged to 30 V and is then connected in series with a 10-μH inductor and a 50-Ω resistor. The potential difference across the capacitor after a long time has passed will be

A 15-Ω resistor is connected across a sinusoidal source that has a peak value of 75 V. The average power delivered by this source is approximately

If you double the frequency in the circuit shown, the capacitive reactance ) of the circuit

A circuit contains a capacitor C μF), an inductor L mH), and an ohmic resistor R Ω) connected in series. If you change the potential across this series combination, the values that change if you neglect thermal effects) are

You connect a 250-Ω resistor, a 1.20-mH inductor, and a 1.80-μF capacitor in series across a 60.0-Hz, 120-V peak) source. When you connect a voltmeter across the inductor in this circuit, the meter reads approximately

A series RLC circuit is driven by a 1.0-kHz oscillator. The circuit parameters are V_rms = 12 V, L = 5.0 mH, C = 4.0 μF, and R = 20 Ω. Under these conditions, the current

When you close the switch S in the figure, the potential between A and B drops to zero. The current in the top loop does not immediately drop to zero because

At what frequency is the reactance ) of a 3.5-mH inductor equal to 10.0 Ω?

A simple generator consists of a single rectangular loop of wire rotating between two magnetic pole faces as shown. Which curve in the graph correctly represents the EMF as a function of the angle between the normal to the plane of the coil and the direction of the magnetic field?

You place a 50-mH inductor across an AC generator that has a maximum EMF of 120 V. The inductive reactance ) when the frequency is 60 Hz is approximately

A series RLC circuit is driven by a 1.0-kHz oscillator. The circuit parameters are L = 5.0 mH, C = 4.0 μF, R = 10 Ω. If you adjust the frequency of the oscillator so that it is at the resonance frequency of the RLC circuit, and if it supplies 3.0 V rms, what is the rms current in the circuit?

How much does the maximum EMF produced by a generator a rotating coil) change if the area of the coil is quadrupled?

The figure shows the voltage and current for a device. The frequency of the voltage is

What is the resistance of a regular 75-W lightbulb connected to a 120-V AC outlet?

For an inductor, the

You connect a 250-Ω resistor, a 1.20-mH inductor, and a 1.80-μF capacitor in series across a 60.0-Hz, 120-V peak) source. The rms current in your circuit is approximately

You connect a 100-Ω resistor, a 800-mH inductor, and a 10.0-μF capacitor in series across a 60.0-Hz, 120-V peak) source. The impedance of your circuit is approximately

You connect a 250-Ω resistor, a 1.20-mH inductor, and a 1.80-μF capacitor in series across a 60.0-Hz, 120-V peak) source. When you connect a voltmeter across the capacitor in this circuit, the meter reads approximately