Physics · Alternating Current

JEE Main 2024 — 6 April, Shift 1 — Question 53

When a dc voltage of 100 V is applied to an inductor, a de current of 5A flows through it. When an ac voltage of 200 V peak value is connected to inductor, its inductive reactance is found to be 203Ω20 \sqrt{3} \Omega. The power dissipated in the circuit is \qquad W.

Answer: 250

Numerical answer — enter this value.

Step-by-step solution

For DC voltage

R=VI=1005=20Ω\mathrm{R}=\frac{\mathrm{V}}{\mathrm{I}}=\frac{100}{5}=20 \Omega

for AC voltage

XL=203Ω\mathrm{X}_{\mathrm{L}}=20 \sqrt{3} \Omega

R=20Ω\mathrm{R}=20 \Omega Z=XL2+R2=3×400+400=40Ω\mathrm{Z}=\sqrt{\mathrm{X}_{\mathrm{L}}^{2}+\mathrm{R}^{2}}=\sqrt{3 \times 400+400}=40 \Omega

Power =irms 2R=\mathrm{i}_{\text {rms }}^{2} \mathrm{R}

=(Vrms Z)2×R=(200240)2×20=250 W=\left(\frac{\mathrm{V}_{\text {rms }}}{\mathrm{Z}}\right)^{2} \times \mathrm{R}=\left(\frac{\frac{200}{\sqrt{2}}}{40}\right)^{2} \times 20=250 \mathrm{~W}

Answer key and solution verified before publishing.

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Exam
JEE Main 2024
Subject
Physics
Chapter
Alternating Current
Topic
Series LCR Circuit and Power Factor