JEE Main 2026 — Jan 28, Shift 2 — Physics solution

JEE Main2026Jan 28, Shift 2Physics

An inductor stores 16 J of magnetic field energy and dissipates 32 W of thermal energy due to its resistance when an a.c. current of 2 A (rms) and frequency 50 Hz flows through it. The ratio of inductive reactance to its resistance is ______ . ( $π = 3.14$ )

Your answer

Solution

Energy stored: $\frac{1}{2} L i_{r m s}^{2} = 16 \Rightarrow L = \frac{32}{i _{r m s}^{2}} = \frac{32}{4} = 8$ H.

Power dissipated: $i_{r m s}^{2} R = 32 \Rightarrow R = \frac{32}{4} = 8 Ω$ .

Inductive reactance: $X_{L} = ω L = 2 π f L = 2 \times 3.14 \times 50 \times 8 = 2512 Ω$ .

$\frac{X _{L}}{R} = \frac{2512}{8} = 314$ .

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