The coil shown in the figure has a resistance of 3.0 ?, 2 turns, a cross-section

Question

The coil shown in the figure has a resistance of 3.0 ?, 2 turns, a cross-sectional area of 0.20 m2, and a field (parallel to the axis of the coil) with a magnitude given by B(t) = (4.0 + 3.0t2) T, where t is in s. What is the value of the induced current in the wire at t=3.5 s? Does this current flow from point A to point B or from point B to point A? (Answer: 2.8 A, B to A)

I have tried using Faraday's Law along with Ohm's Law after and cannot come up with the answer indicated. Please show work. Thanks

Explanation / Answer

here figure is not visible....so i can calculate only magnitude of magnetic field...

so,

emf induced= d(nB.A)/d(t)

=0.20*2 *d(4.0 + 3.0t^2)/d(t)

=0.2*2 *6t

at t=3.5s, emf=0.2*2 *6*3.5 volt=8.4 volt

so current induced=emf/resistance=8.4/3=2.8 amp

and u can calculate the direction of current by the lenz law...

Lenz's law states that the current induced in a circuit due to a change or a motion in a magnetic field is so directed as to oppose the change in flux or to exert a mechanical force opposing the motion....

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