Exam 19: Dc Circuits

A multiloop circuit is shown in the figure, but some quantities are not labeled. Find the current $I _ { 2 }$ if the batteries are ideal. (It is not necessary to solve the entire circuit.)

A $9.00 - \mu \mathrm { F }$ and a 12.0- $\mu \mathrm { F }$ capacitor are connected together, and this combination is connected across a 25.0-V potential difference. How much electric energy is stored in the combination if they are connected (a) in parallel or (b) in series?

At what frequency does a $10 - \mu \mathrm { F }$ capacitor have a reactance of $1200 \Omega$ ?

A series circuit containing an inductor and a resistor is driven by a $120 - \mathrm { V } 60 - \mathrm { Hz }$ voltage source. The resistance is equal to $20.0 \Omega$ and the inductance is $160 \mathrm { mH }$ . What is the phase angle between the current the the applied voltage?

The area of a rectangular loop of wire is $3.6 \times 10 ^ { - 3 } \mathrm {~m} ^ { 2 }$ . The loop is placed in a uniform magnetic field that changes steadily from $0.20 \mathrm {~T}$ to $1.4 \mathrm {~T}$ in $1.6 \mathrm {~s}$ . The plane of the loop is perpendicular to the direction of the magnetic field. What is the magnitude of the induced emf in that loop?

In the figure, which of the phasor diagrams represents a series $R L C$ circuit driven at resonance?

A $10 - \Omega$ resistor is connected in series with a $20 - \mu \mathrm { F }$ capacitor. What is the impedance at $1.0 \mathrm { kHz }$ ?

Three resistors with resistances of $2.0 \Omega , 6.0 \Omega$ , and $12 \Omega$ are connected across an ideal dc voltage source $V$ , as shown in the figure. If the total current in the circuit is $I = 5.0 \mathrm {~A}$ , what is the current through the 12- $\Omega$ resistor?

For the circuit shown in the figure, $V = 20 \mathrm {~V} , C = 10 \mu \mathrm { F } , R = 0.80 \mathrm { M } \Omega$ , and the battery is ideal. Initially the switch $\mathrm { S }$ is open and the capacitor is uncharged. The switch is then closed at time $t =$ $0.00 \mathrm {~s}$ . What is the potential difference across the resistor $20 \mathrm {~s}$ after closing the switch?

A network of capacitors is mostly inside a sealed box, but one capacitor $C X$ is sticking out, as shown in the figure. When you connect a multimeter across points $a$ and $b$ , it reads $27.0 \mu \mathrm { F }$ . What is $C X$ ?

For the circuit shown in the figure, calculate the emf's $\varepsilon 1$ and $\varepsilon 3$ , assuming that the batteries are ideal. Note that two currents are shown.

A $20.0 - \mathrm { mH }$ inductor is connected in series with a $100 - \Omega$ resistor at $1.00 \mathrm { kHz }$ in an ac circuit. What is the phase angle of this circuit?

For the circuit shown in the figure, $R _ { 1 } = 18 \Omega , R _ { 2 } = 44 \Omega , R _ { 3 } = 33 \Omega , R _ { 4 } = 14 \Omega , R _ { 5 } = 12 \Omega$ , $V _ { 1 } = 18 \mathrm {~V} , V _ { 2 } = 12 \mathrm {~V}$ , and the batteries are ideal. Determine $I _ { 1 }$ and $I _ { 2 }$ .

The inductance of a solenoid that is $16.0 \mathrm {~cm}$ long and has a cross-sectional area of $1.00 \times 10 ^ { - 4 } \mathrm {~m} ^ { 2 }$ is $1.00 \mathrm { mH }$ . How many turns of wire does this solenoid have? $\left( \mu _ { 0 } = 4 \pi \times 10 ^ { - 7 } \mathrm {~T} \cdot \mathrm { m } / \mathrm { A } \right)$

In the circuit shown in the figure, the $60 - \mathrm { Hz }$ ac source has a voltage amplitude of $120 \mathrm {~V}$ , the capacitive reactance is $820 \Omega$ , the inductive reactance is $330 \Omega$ , and the resistance is $550 \Omega$ . What is the capacitance $C$ of the capacitor?

A series ac circuit has a resistance of $2.0 \mathrm { k } \Omega$ , a capacitance of $8.0 \mu \mathrm { F }$ , and an inductance of $9.0 \mathrm { H }$ . If the frequency of the alternating current is $4.0 / \pi \mathrm { kHz }$ , by what angle does the voltage lead the current?

The network shown is assembled with uncharged capacitors $X , Y$ , and $Z$ , with $C X = 4.0 \mu F , C Y =$ $6.0 \mu \mathrm { F }$ , and $\mathrm { C } _ { \mathrm { Z } } = 5.0 \mu \mathrm { F }$ . The switches $\mathrm { S } _ { 1 }$ and $\mathrm { S } _ { 2 }$ are initially open, and a potential difference $V _ { a b } =$ $120 \mathrm {~V}$ is applied between points $a$ and $b$ . After the network is assembled, switch $\mathrm { S } _ { 1 }$ is then closed, but switch $\mathrm { S } _ { 2 }$ is kept open. What is the final potential difference across capacitor $\mathrm { X }$ ?

A transformer is a device used to

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

What is the potential drop from point A to point B for the circuit shown in the figure? The battery is ideal, and all the numbers are accurate to two significant figures.