State Kirchhoff’s second law.
Two batteries, each with electromotive force (e.m.f.) $6.0\,\text{V}$ and negligible internal resistance, are arranged in series with three resistors, as shown in Fig. 5.1. Resistor X has resistance $4.0\,\Omega$ and resistor Y has resistance $1.5\,\Omega$.
The resistance $R$ of the variable resistor is adjusted until the voltmeter in the circuit shows zero. Calculate the current $I$ in the circuit.
Calculate the resistance $R$.
Resistors X and Y are wires made from the same material. The diameter of the wire of X is twice the diameter of the wire of Y. Determine the ratio average drift speed of free electrons in X : average drift speed of free electrons in Y.
The resistance $R$ of the variable resistor is now increased. State and explain the effect of the increase in $R$ on the power transformed by each of the batteries.
Resistors $X$ and $Y$ are wires made from the same material. The diameter of the wire of $X$ is twice the diameter of the wire of $Y$. Determine the ratio $\dfrac{\text{average drift speed of free electrons in } X}{\text{average drift speed of free electrons in } Y}$.
The resistance $R$ of the variable resistor is now increased. State and explain the effect of the increase in $R$ on the power transformed by each of the batteries.