WAEC Physics 2024 Paper

Concept:Resistance of a wire depends on its length, material, and cross-sectional area.Explanation:The resistance of a wire is given by $R = \frac{\rho l}{A}$.Here, $\rho$ and $l$ are the same for all the wires.So, $R$ is inversely proportional to $A$: $R \propto \frac{1}{A}$.The cross-sectional area is $A = \pi r^2 = \pi \left(\frac{d}{2}\right)^2$.Therefore, the smallest diameter gives the smallest area and hence the highest resistance.Wire E has the smallest diameter of $1\,\text{mm}$.Answer:Wire E has the highest resistance. Correct option: A. E.