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A straight horizontal conductor of length 20 m lies along the east–west direction and is moving downward with speed 5.0 m/s, perpendicular to the horizontal component of Earth’s magnetic field, which has magnitude 0.30 × 10⁻⁴ Wb/m². What is the instantaneous induced emf across the wire?
- 3 mV
- 4.5 mV
- 1.5 mV
- 6.0 mV
Correct answer: 3 mV
Solution
The induced emf in a conductor moving through a magnetic field can be calculated using Faraday's law of electromagnetic induction, which states that emf = B * L * v, where B is the magnetic field strength, L is the length of the conductor, and v is the velocity. Substituting the values (B = 0.30 × 10⁻⁴ Wb/m², L = 20 m, v = 5.0 m/s) gives an induced emf of 3 mV.
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