27. Resistors & DC Circuits

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?

An aluminum wire consists of the three segments shown in FIGURE P27.64. The current in the top segment is 10 A. For each of these three segments, find the current density J. Place your results in a table for easy viewing.

A superconducting magnet carries a 100 A current through a 0.50-mm-diameter superconducting wire that is wound into a coil. How much charge flows through the wire in 15 minutes?

What diameter should the nichrome wire in FIGURE P27.62 be in order for the electric field strength to be the same in both wires?

The current in a 2.0 mm x 2.0 mm square aluminum wire is 2.5 A. What are (a) the current density and (b) the electron drift speed?