What does the term volt mean?
A battery with electromotive force (e.m.f.) $7.0\,\text{V}$ and negligible internal resistance is linked in series to three components, as shown in Fig. 6.1. Resistor X has resistance of $5.2\,\Omega$. The filament wire of lamp Y has resistance of $6.0\,\Omega$. The potential difference across resistor Z is $1.4\,\text{V}$.
Calculate the current flowing in the circuit.
Determine the resistance for resistor Z.
Calculate the percentage efficiency at which the battery delivers power to the lamp.
The filament wire in the lamp is made from a metal whose resistivity at its operating temperature in the circuit is $3.7 \times 10^{-7}\,\Omega\,\text{m}$. Determine, for the filament wire, the value of $\alpha$ where $\alpha = \dfrac{\text{cross-sectional area}}{\text{length}}$.
Determine, for the filament wire, the value of $\alpha$ given that $\alpha = \frac{\text{cross-sectional area}}{\text{length}}$.