27. Resistors & DC Circuits

Which of the following best describes an electrical current?

Which statement correctly describes the formation of an $\mathrm{electric current}$?

Which of the following best describes how a switch functions in an electrical circuit?

Which type of electric current is most commonly supplied to homes for powering appliances?

Which of the following is the correct unit for measuring electric current?

Which of the following is the standard unit of measurement for electric current?

If a wire delivers a charge $Q$ in a time $t$ with current $I$, what is the current in a second wire that delivers twice as much charge ($2Q$) in half the time ($\frac{t}{2}$)?

Which type of electric current is typically produced by a standard chemical battery?

In a circuit consisting of a battery connected in series with a resistor and an ideal capacitor, what is the current through the battery after a very long time has passed?

A strip of silicon 1.8 cm wide and 1.0 mm thick is immersed in a magnetic field of strength 1.3 T perpendicular to the strip (Fig. 40–53). When a current of 0.28 mA is run through the strip, there is a resulting Hall effect voltage of 18 mV across the strip (Section 27–8). How many electrons per silicon atom are in the conduction band? The density of silicon is 2330 kg/m³.

Which component is used to measure the current $I$ in a circuit?

In a simple circuit consisting of a battery with voltage $V$ and a resistor with resistance $R$ connected in series, what is the current through the battery?

In a series circuit, how does the total current change if additional resistors are added to the circuit, assuming the voltage source remains constant? $I$ is the current, $V$ is the voltage, and $R$ is the resistance, related by $I=\frac{V}{R}$.

A lightning bolt hits the ground carrying a current of 3 × 10⁴ A. If the strike lasts 50 ms, how much charge enters the ground?