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QJEEAdv20Ph4d7d: JEE Advanced 2020 Physics - Class 12 JEEAdv20Ph4d7d Solution: The inductors of two LR circuits are placed next to each other, …

The inductors of two LR circuits are placed next to each other, as shown in the figure. The values of the self-inductance of the inductors, resistors, mutual-inductance and applied voltages are specified in the given circuit. After both the switches are closed simultaneously, the total work done by the batteries against the induced EMF in the inductors by the time the currents reach their steady state values is _________ mJ.

JEE Advanced 2020 Paper 2 Offline Physics - Electromagnetic Induction Question 9 English

Step-by-Step Verified Solution

Mutual inductance is producing flux in same direction as self-inductance.

∴ U=12L1I12+12L2I22+MI1I2

⇒U=12×(10×10−3)12+12×(20×10−3)×22+(5×10−3)×1×2

=55 mJ

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