8. A magnetic field given by B（t）=0.2t - 0.5t2 T is directed perpendicular to the plane of a circular coil containing 25 turns of radius 1.8 cm and whose total resistance is 1.5Ω . What is the power dissipation at 3 s ?
(A) 2.28 mW
(B) 3.38 mW
(C) 4.52 mW
(D) 5.56 mW
(E) 6.72 mW
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