JAMB Physics 2019 Paper

Concept:Reactance is the opposition an inductor (or capacitor) offers to alternating current, measured in ohms, similar to resistance.Explanation:For an inductor, reactance ($X_L$) is defined as the ratio of the amplitude of the alternating voltage across it to the amplitude of the alternating current through it.This can be written as:$$X_L = \frac{V_0}{I_0}$$Where $V_0$ is the amplitude of voltage and $I_0$ is the amplitude of current.Therefore, reactance is obtained by dividing the voltage amplitude by the current amplitude.Answer:A. Reactance = (Amplitude of voltage) $\div$ (Amplitude of current)