1. The problem statement, all variables and given/known data A closed wire loop in the form of a square of side 4.0 cm is mounted with its plane horizontal. The loop has a resistance of 2.0 * 10-3 Ω, and negligible self inductance. The loop is situated in a magnetic field of strength 0.70 T directed vertically downwards. When the field is switched off, it decreases to zero at a uniform rate in 0.80 s. What is: (a) the current induced in the loop, (b) the energy dissipated in the loop during the change in the magnetic field? Show on a diagram, justifying your statement, the direction of the induced current. Answers: (a) 0.70 A, (b) 7.8 * 10-4 J. 2. The attempt at a solution (a) E = - N d Φ / d t, where Φ = B A = 0.7 * (0.04 * 0.04) E = - 1 * ((0.7 * (0.04 * 0.04)) / 0.8) = 1.4 * 10-3 V. I = V / R = 1.4 * 10-3 / 2 * 10-3 = 0.7 A. (b) P = I2 R = V2 / R = 0.72 * 2 * 10-3 = 9.8 * 10-4 J. Why this answer is larger than the given one?