A coil of 150 loops is pulled in 0.06s from poles of the magnet, which decreases the magnetic flux linked with the coil from 6 x 10^-4 Wb to 2 x 10^-4 Wb. The average emf induced in the coil is:
Correct answer: A. 1 V
- A. 1 V
- B. 1.5 V
- C. 0.1 V
- D. 0.15 V
Explanation
We can use Faraday's law of induction; emf=−N(ΔΦ/Δt )The change in magnetic flux (ΔΦ) is:ΔΦ=Φfinal −Φinitia = (2×10−4 Wb)−(6×10−4 Wb) = −4×10−4 WbNow, we can calculate the average emf:emf=−150×(−4×10−4 Wb) / 0.06 s =1 VSo, the average emf induced in the coil is 1 V.
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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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