Exam 9: Alternating-Current Circuits

Use the following figure for the next three problems. The battery has a voltage V = 6 V, the inductance of the inductor L = 12 mH and the capacitance of the capacitor C = 8 $\mu$ F. Assume that the inductor and the wires have zero resistance. -The switch S was at position a for a long time when it is switched to b. Describe the current flow in the right loop.

Use the following figure to answer the next problem: -The diagram that correctly represents the phase relationship between the current through the resistor and the voltage across the resistor in a circuit containing an inductor L, a capacitor C, and a resistor R all connected in series is

A series RLC circuit with L = 5 H, C = 10 µF, and R = 10 $\Omega$ is driven by a generator with a maximum EMF of 100 V and a variable frequency. The Q value of this circuit is

You connect a 250- $\Omega$ resistor, a 1.20-mH inductor, and a 1.80- $\mu$ F capacitor in series across a 60.0-Hz, 120-V (peak) source. The rms current in your circuit is approximately

If you place a 40.0- $\mu$ F capacitor across a generator that has a maximum EMF of 120 V, the capacitive reactance when the frequency is 60 Hz is approximately

As you increase the frequency in this circuit from zero,

An AC generator supplies 22 rms volts to a 30- $\Omega$ resistor at 50 Hz. What is the maximum current in 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- $\Omega$ resistor. The potential difference across the inductor after a long time has passed will be

Use the following figure for the next two problems. -The figure shows the voltage and current for a device. The frequency of the voltage is

If you double the peak voltage in an AC circuit, the rms voltage

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

The resistance of the armature windings of DC motor is 5 $\Omega$ . The motor is connected to a 120 V line. When the motor is spinning at full speed, it draws a current of 4 A. The bACk EMF at full speed is

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?

A 5-µF capacitor is charged to 30 V and is then connected across a 10-µH inductor. The maximum value of the current in this circuit is

You connect a 250- $\Omega$ resistor, a 1.20-mH inductor, and a 1.80- $\mu$ F 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

You connect a 250- $\Omega$ resistor, a 1.20-mH inductor, and a 1.80- $\mu$ F capacitor in series across a 60.0-Hz, 120-V (peak) source. The maximum current in your circuit is approximately

You connect a 100- $\Omega$ resistor, a 800-mH inductor, and a 10.0- $\mu$ F capacitor in series across a 60.0-Hz, 120-V (peak) source. In this circuit,

If you connect a 12-V rms AC power supply that operates at 5.0 kHz to a 20- $\mu$ F capACitor, what is the rms current in the circuit? (neglect any resistance)

Use the following figure for the next three problems. An AC power supply, V = 20 V sin $\omega$ t where $\omega$ = 200 rad/s is connect to an inductor L = 180 mH and a capacitor C = 25 $\mu$ F. XL = 36 ohms, XC = 200 ohms, Z = 43.9 ohms -What is the peak current flow through the inductor?

Electronic devices use electrical energy even when they are on standby. Calculate the percent of energy used per day for the following entertainment equipment in the standby mode assuming that they are plugged in all the time. Device Standby Power Power when on Hours on per day DVD player 1 W 75 W 4 TV 2 W 100 W 6 Tuner 1 W 150 W 4