1. The problem statement, all variables and given/known data Imagine a pliable round metal loop that can expand or contract. In a region with a constant magnetic field B0 that is oriented perpendicular to the plane of the loop, suppose that the loop expands, with its radius growing with time as r = r0(1+at2). As the loop expands and grows thinner, its resistance per unit length changes according to R = R0(1+bt2). Find an expression for the current induced in the loop as a function of time. To check your answer, suppose that B0 = 3.30 mT, r0 = 16.5 cm, R0 = 7.55Ohm/m, a = 0.245 x 10-4 s2, and b = 0.590 x 10-2 s2. What is the value of the induced current at t = 27.5 s? (Note: Give the direction of the current where when viewed from above a positive current will move counterclockwise.) 2. Relevant equations V = IR EMF = d(flux)/dt flux = Sb*dA (integral of dot product of B and dA, or |B||dA|cos(90) in this case --> BdA) 3. The attempt at a solution First, find EMF induced and then use V = IR to solve for I. This is the equation I came up with: I(t) = B∏(ro(1+at^2))^2/(Ro(1+bt^2) = 7E-6 A This answer wasn't correct in my online homework program. The negative value was also incorrect. Then, I reread the question and saw the part about the equation for resistance being per unit length, so I got this equation (multiply above by circumference): I(t) = 2B∏^2(ro(1+at^2))^3/(Ro(1+bt^2) = 7E-6 A It didn't change my answer. Which equation is right (if either)?