Calculate the current through the resistance wire.
Calculate how many free electrons pass through the resistance wire in $50\,\text{s}$.
Calculate the wire's resistance.
The resistance wire in the circuit is made of a metal with resistivity $1.4 \times 10^{-6}\,\Omega\,\text{m}$. Its cross-sectional area is $0.25\,\text{mm}^2$. Determine the wire's length.
In Fig. 6.1, the original resistance wire is replaced by a second resistance wire. The second wire has a larger diameter than the original, and there are no other differences between them. Referring to resistance, state and explain whether the power dissipated by the second wire is greater than, smaller than or equal to the power dissipated by the original wire.
In Fig. 6.1, a second battery with e.m.f. $8.0\,\text{V}$ and negligible internal resistance is connected in parallel with the original battery and the original resistance wire, as shown in Fig. 6.2. Referring to the current in the resistance wire, state and explain whether adding the second battery makes the power in the original resistance wire decrease, increase or remain unchanged.