Define resistance in a circuit.
A cylindrical metal wire with length $2.4\,\text{m}$, cross-sectional area $8.0 \times 10^{-6}\,\text{m}^2$, and resistance $0.33\,\Omega$ carries a current of $4.7\,\text{A}$. Determine the resistivity of the metal from which the wire is made.
Calculate the total charge that passes through the wire in $5.0\,\text{minutes}$.
The free electrons (charge carriers) in the wire have an average drift speed of $0.16\,\text{mm s}^{-1}$. Determine the number density of charge carriers in the metal.
The wire in (b) can be treated as a fixed resistor. It is connected in series with a thermistor and a battery with negligible internal resistance. Use circuit symbols to complete Fig. 6.1 so that it shows the circuit diagram for this arrangement.
Explain, without calculation, how the power dissipated in the wire changes when the temperature of the thermistor is increased.