State Kirchhoff’s first law in words.
Kirchhoff’s first law is connected to the conservation of a particular quantity. State that quantity.
A battery with electromotive force (e.m.f.) $8.0\,\text{V}$ and internal resistance $2.0\,\Omega$ is connected to resistor $X$ and wire $Y$, as shown in Fig. 6.1. The resistance of $X$ is $15\,\Omega$. The resistance of $Y$ is $R_Y$. The current in the battery is $2.5\,\text{A}$. Calculate the thermal energy dissipated inside the battery in a time of $5.0$ minutes.
Calculate the battery terminal potential difference.
Determine the value of $R_Y$.
A new wire $Z$ has the same length but a smaller resistance than wire $Y$. State two possible differences between wire $Z$ and wire $Y$ that would each, on its own, make wire $Z$ have a smaller resistance than wire $Y$.
Wire $Y$ is replaced by wire $Z$ in the circuit. Considering the current in the battery, state and explain how changing the wires affects the total power output of the battery.
Determine the value of $R_Y$.
A new wire Z has the same length but a smaller resistance than wire Y. State two possible differences between wire Z and wire Y that would each, on their own, make wire Z’s resistance smaller than wire Y’s.\n\nFirst difference:\n\nSecond difference:
Wire Y is replaced by wire Z in the circuit. By referring to the current in the battery, state and explain how this affects the battery’s total power output.