The current in a coil of inductance 5H decreases at the rate of 2A/s. The induced e.m.f is:
Correct answer: D. -10 V
- A. 2.5 V
- B. 0.4 V
- C. 10 V
- D. -10 V
Explanation
To find the induced electromotive force (e.m.f) in a coil when the current is changing, you can use the formula: ε=−L ΔI/Δt Given that the inductance ( L ) is 5H and the rate of change of current ( ΔI/Δt ) is 2A/s, we can substitute these values into the formula: ε=−5×2 ε=−10 VSo, the induced e.m.f is -10 volts. The negative sign indicates that the induced e.m.f is in a direction that opposes the change in current, according to Lenz's Law.
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About Faraday's Law
Faraday's law states that an induced electromotive force equals the rate of change of magnetic flux linkage through a circuit. Questions cover changing field, area, angle or motion, the negative sign associated with Lenz's law, and the distinction between induced emf and the current that may flow in a closed circuit.
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