Parts a and b of the drawing show the same uniform and constant (in time) magnet
ID: 1498671 • Letter: P
Question
Parts a and b of the drawing show the same uniform and constant (in time) magnetic field B directed perpendicularly into the screen over a rectangular region. Outside this region, there is no field. Also shown is a rectangular coil (one turn), which lies in the plane of the screen. In part a the long side of the coil (length = L) is just at the edge of the field region, while in part b the short side (width = W) is just at the edge. It is known that L/W = 3.10. In both parts of the drawing the coil is pushed into the field with the same velocity v until it is completely within the field region. The magnitude of the emf induced in the coil in part a is 0.205 V. What is its magnitude in part b?
Explanation / Answer
This problem relates to motional EMF. V = vLB, where L is the length of the wire that is perpendicular to velocity v. In this case, L(b)/L(a) = 1/3.10, so V(b) = V(a)/3.10 = 0.06613 V.