As shown below, a square loop of wire of side a moves through a uniform magnetic field of magnitude B perpendicular to the page at constant velocity directed to the right. Judd says that the emf induced in the loop is zero. Roger claims that it has magnitude B . Which one, if either, is correct, and why? A) Judd, because the magnetic flux through the loop is constant. B) Roger, because the magnetic flux through the loop is constant. C) Judd, because the magnetic flux through the loop is not constant if . D) Roger, because the magnetic flux through the loop is not constant if . E) Roger, because the magnetic flux through the loop is Φ_B = 0.

Question

Quizplus · Accepted Answer

The emf induced in a loop of wire is given by the equation emf = -N(dΦ/dt), where N is the number of turns in the loop and Φ is the magnetic flux through the loop. Since the loop is moving at a constant velocity perpendicular to the uniform magnetic field, the magnetic flux through the loop is constant. Therefore, the emf induced in the loop is zero (Judd's claim). Roger's claim is incorrect because the magnitude of the emf induced is not proportional to the magnetic field strength B, but rather to the rate of change of the magnetic flux through the loop.

As Shown Below, a Square Loop of Wire of Side