Exam 19: Dc Circuits

For the circuit shown in the figure, the battery is ideal and all quantities are accurate to two significant figures. Find the current through (a) the 1.0- $\Omega$ resistor, (b) the $3.0 - \Omega$ resistor, and (c) the 4.0- $\Omega$ resistor.

A resistance of $55 \Omega$ , a capacitor of capacitive reactance $30 \Omega$ , and an inductor of inductive reactance $30 \Omega$ are connected in series to a $110 - \mathrm { V } \mathrm { rms } , 60 - \mathrm { Hz }$ power source. What rms current flows in this circuit?

If the primary coil of a transformer contains more loops than the secondary coil then it is a

A series circuit consists of a $0.440 - \mathrm { H }$ inductor, a 380.0- $\Omega$ resistor, a 5.70- $\mu \mathrm { F }$ 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 impedance of an $R C$ circuit with a $200 - \Omega$ iresistor s $1060 \Omega$ . If the frequency of the applied ac voltage is $20.0 \mathrm {~Hz}$ , what is the capacitance of the capacitor?

A battery has an emf $\varepsilon = 43.0 \mathrm {~V}$ and an internal resistance $r = 8.0 \Omega$ , as shown in the figure. When the terminal voltage $V _ { a b }$ is equal to $34.0 \mathrm {~V}$ , the current through the battery, including its direction, is closest to

A certain 20-A circuit breaker trips when the current in it equals $20 \mathrm {~A}$ . What is the maximum number of $100 - W$ light bulbs you can connect in parallel in an ideal $120 - \mathrm { V }$ dc circuit without tripping this circuit breaker?

A $120 - \mathrm { V }$ rms voltage at $1000 \mathrm {~Hz}$ is applied to an inductor, a $2.00 - \mu \mathrm { F }$ capacitor and a $100 - \Omega$ resistor. If the rms value of the current in this circuit is $0.680 \mathrm {~A}$ , what is the inductance of the inductor?

As shown in the figure, one end of a metal bar is in contact with a circular rail and the other end is pivoted at $\mathrm { P }$ . A steady uniform, magnetic field $B$ into the page is present. As the bar rotates about point $P$ in a clockwise direction, the direction of the induced current through the resistor $R$ is

For the circuit shown in the figure, $V = 60 \mathrm {~V} , C = 40 \mu \mathrm { F } , R = 0.90 \mathrm { M } \Omega$ , and the battery is ideal. Initially the switch $\mathrm { S }$ is open and the capacitor is uncharged. The switch is then closed at time $t =$ $0.00 \mathrm {~s}$ . At a given instant after closing the switch, the potential difference across the capacitor is twice the potential difference across the resistor. At that instant, what is the charge on the capacitor?

As shown in the figure, a metal bar is in contact with a pair of parallel rails and is in motion with an upward velocity of magnitude $v$ . A uniform magnetic field is present, directed downward as shown. The direction of the induced current through the resistor $R$ is

For the circuit shown in the figure, both batteries are ideal. What current flows in the solid wire connecting the upper left and lower left corners of the circuit?

What is the power factor of an $R L C$ ac series circuit with an inductive reactance of $174 \Omega$ , a capacitive reactance of $60 \Omega$ and a resistance of $0.10 \mathrm { k } \Omega$ ?

The wire in the figure carries a current $I$ that is decreasing with time at a constant rate. The wire and the three loops are all in the same plane. What is true about the currents induced in each of the three loops shown?

A system of four capacitors is connected across a $90 - V$ voltage source as shown in the figure. (a) What is the potential difference across the plates of the $6.0 - \mu \mathrm { F }$ capacitor? (b) What is the charge on the $3.0 - \mu \mathrm { F }$ capacitor?

As shown in the figure, a circuit consists of a resistor $R = 17 \Omega$ in series with an ideal inductor $L = 49 \mathrm { H }$ having no resistance. At time $t = 0 \mathrm {~s}$ , there is a 12-A current in the circuit. At that instant, what is the rate of change of the current?

The three loops of wire shown in the figure are all hanging in the same uniform magnetic field $\vec { B }$ that is perpendicular to the page and does not vary with time. Loop 1 swings back and forth like the bob in a pendulum, Loop 2 rotates about a vertical axis, and Loop 3 oscillates up and down at the end of a spring. Which loop (or loops) will have an emf induced in them?

A bar magnet is pushed through a coil of wire of cross-sectional area $0.020 \mathrm {~m} ^ { 2 }$ as shown in the figure. The coil has seven turns, and the rate of change of the strength of the magnetic field in it due to the motion of the bar magnet is $0.040 \mathrm {~T} / \mathrm { s }$ . What is the magnitude of the induced emf in that coil of wire?

Four $16 - \mu \mathrm { F }$ capacitors are connected in combination. What is the equivalent capacitance of this combination if they are connected (a) in series? (b) in parallel? (c) such that two of them are in parallel with each other and that combination is in series with the remaining two capacitors?

A flat circular loop of radius 0.10 m is rotating in a uniform magnetic field of 0.20 T. Find the magnetic flux through the loop when the plane of the loop and the magnetic field vector are Parallel.