A circular coil of radius r = 5 cm and resistance R = 0.2 Ω is placed in a uniform magnetic field perpendicular to the plane of the coil. The magnitude of the field changes with time according to B = 0.5 e^-0.2t T. What is the magnitude of the current induced in the coil at the time t = 2 s?

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Quizplus · Accepted Answer

The induced emf (ε) is given by Faraday's law: ε = -dΦ/dt, where Φ = B * A is the magnetic flux. For a circular coil, A = πr². At t = 2 s, B = 0.5e^(-0.2*2) T. Calculate dB/dt, then ε = A * dB/dt. Finally, use Ohm's law: I = ε/R to find the current.

A Circular Coil of Radius R = 5 Cm and Resistance