JAMB Physics 2021 Paper

Concept:Inductive reactance is the opposition an inductor offers to alternating current.It depends on the frequency of the supply and the inductance of the coil.The formula is $X_L = 2\pi f L$.Explanation:From the question, the inductance is $L = 2\ \mathrm{H}$.The frequency of the A.C. supply is $f = \frac{50}{\pi}\ \mathrm{Hz}$.Substitute these values into the inductive reactance formula:$X_L = 2\pi f L = 2\pi \times \frac{50}{\pi} \times 2$The $\pi$ cancels out, so:$X_L = 2 \times 50 \times 2 = 200\ \Omega$Thus, the reactance of the inductor is $200\ \Omega$.Answer:The correct option is A. $200\ \Omega$.