0877 #18 (induced current)
Posted: Tue Oct 11, 2011 12:52 pm
Hey folks, I'm having trouble with this problem about induced current (0877 #18). I'm hoping someone can help me arrive at the quick, correct solution.
So there's an induced EMF $$V = - \frac{\partial \Phi_B}{\partial t}$$, so all we really need is how the magnetic flux through the loop is changing.
What I'm visualizing is the field lines going into the south pole and coming out of the north pole, along the magnet axis. So there would be an induced current to "cancel out" the change in flux, which I think would be counter-clockwise in the figure. That gives answer (C), which is wrong. The correct answer is (E).
Could someone help? Thanks!
So there's an induced EMF $$V = - \frac{\partial \Phi_B}{\partial t}$$, so all we really need is how the magnetic flux through the loop is changing.
What I'm visualizing is the field lines going into the south pole and coming out of the north pole, along the magnet axis. So there would be an induced current to "cancel out" the change in flux, which I think would be counter-clockwise in the figure. That gives answer (C), which is wrong. The correct answer is (E).
Could someone help? Thanks!