a rectangular loop with a=6.0 cm, and b=4.0 cm, moving with a velocity v=8.0 cm/s into an area where the magnetic field is uniform, pointing into the page, and whose magnitude is B= 440 mT.

Question

a) What is in volts the induced emf in the loop when the loop is moving in a region where the magnetic field is uniform?

b) We stop the loop and instead, while keeping it at the region of uniform field, we pull two opposite ends of the loop apart until the overall area of the loop is zero. If it takes 0.21 seconds to do that, what is in volts the induced emf in the loop?

Answer 1

a) No change in the magnetic field and the area thus no flux change with time. Thus induced emf=0
b)Change in the area is=0.06*0.04 m^2-0= 0.0024 m^2
Thus the induced emf =change in flux
=B*(change in area)/t
=0.440*0.0024/0.21
=0.005 V