Exam 5: Electric Current and Direct-Current Circuits

In the circuit element shown, the current through the 6- $\Omega$ resistor is approximately

A 1.2- $\mu$ F capacitor in a flash camera is charged by a 1.5-V battery. When the camera flashes, this capacitor is discharged through a resistor. The time constant of the circuit is 10 ms. What is the value of the resistance?

A 0.120- $\mu$ F capacitor, initially uncharged, is connected in series with a 10.0-k $\Omega$ resistor and a 12.0-V battery of negligible internal resistance. The charge on the capacitor after a very long time is approximately

A sensitive galvanometer has a resistance of 180 $\Omega$ and requires 2.4 $\mu$ A of current to produce a full-scale deflection. The shunt resistance needed to construct an ammeter that gives full-scale deflection for a current of 1.0 mA is approximately

Use the following figures to answer the next five problems. -An uncharged capacitor and a resistor are connected in series to a battery as shown. If $\varepsilon$ = 15 V, C = 20 $\mu$ F, and R = 4.0* 10⁵ $\Omega$ , the time constant of the circuit is approximately

Which of the following statements is false?

The conservation of charge in an electric circuit is closely related to which of the following?

In the above circuit, $\varepsilon$ ₁ = 9 V, $\varepsilon$ ₂ = 6 V, and $\varepsilon$ ₃ = 6 V. Also R₁ = 25 $\Omega$ , R₂ = 125 $\Omega$ , and R₃ = 55 $\Omega$ . Find the current flowing through R₂.

In this circuit, the batteries have negligible internal resistance and the ammeter has negligible resistance. The current through the ammeter is

If electric energy costs 10 cents per kilowatt-hour, how many cents does it cost to keep a 660-W toaster in steady operation for 30 min?

The power delivered by the battery in the figure is

The current in the circuit shown is

The seemingly instantaneous propagation of electric current in a wire when a switch is closed can be understood in terms of

Battery A has a relatively high internal resistance, whereas battery B has a low internal resistance. If both batteries provide the same current to some external circuitry, which of the following statements is likely to be true?

You can pay a lot of money for fancy connecting cables between your audio/video equipment components. Some of the more expensive ones use silver wire rather than copper. Calculate the difference in resistance between a silver and a copper cable with the same 12-gauge diameter of 2.05 mm and length of 3 m (hence total length = 6m). (Use $\rho$ (Cu) = 1.7 * 10^-8 $\Omega$ /m and $\rho$ (Ag) = 1.6 * 10^-8 $\Omega$ /m. Unfortunately (or fortunately), there are many other factors that go into making an interconnect cable than simple resistance considerations.)

An uncharged capacitor and a resistor are connected in series to a battery as shown. If $\varepsilon$ = 15 V, C = 20 $\mu$ F, and R = 4.0 *10⁵ $\Omega$ , the charge on the capacitor as a function of time is

In a certain particle accelerator, a current of 800 $\mu$ A is carried by a 6.00-MeV proton beam that has a radius of 1.50 mm. The mass of a proton is 1.67 F* 10^-27 kg. If the beam hits a target, how many protons hit the target in 5 s?

You want to use three resistors in a circuit. If each of them has a resistance of 2 $\Omega$ , the configuration that will give you an equivalent resistance of 3 $\Omega$ is

A capacitor, initially uncharged, is connected in series to a 10-k $\Omega$ resistor and a 9.0-V battery. What is the initial current in this circuit?

In this circuit, the current through the 5- $\Omega$ resistor is approximately