Answer to Question #319916 in Electricity and Magnetism for jam

Question

An aluminum disk is held between the poles of a powerful magnet and then pulled out. The person pulling on the disk feels an opposing force due to currents induced through Faraday's law. Explain why the magnitude of the force becomes larger as the disk is pulled faster.

Answer 1

An aluminum disk is held between the poles of a powerful magnet and then pulled out. The person pulling on the disk feels an opposing force due to currents induced through Faraday's law

Change in magnetic flux through area of any loop induces emf in the loop. From the Faraday’s law, induced electro motive force

Faraday law

Emf

$e=-N\frac{d\phi}{dt}$

$\phi=B.A=BAcos\theta$