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In the circuit, X is connected to Y for a long time (an inductor L charges through R1 from EMF E), then X is switched to Z so the inductor discharges through R2. What is the total heat produced in R2?
- L*E² / (2*R1²)
- L*E² / (2*R2²)
- L*E² / (2*R1*R2)
- L*E²*R2 / (2*R1²)
Correct answer: L*E² / (2*R1²)
Solution
After a long time the inductor current is steady at I0 = E/R1 (inductor acts as a wire). When switched to discharge through R2, all the energy stored in the inductor is dissipated as heat in R2.
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