Question

A magnet is moved towards the coil

1. quickly
2. slowly

What will be the work done?

Answer 1

Induced Electromotive Force:

1. It is the potential difference in a coil due to the changes in the magnetic flux through it.
2. It is given as $InducedEMF=\frac{d\varnothing }{dt}$.
3. It is directly proportional to the rate of change of flux.

Work done by Induced Electromotive Force:

1. The work done by emf is equal to the product of emf and charge.
2. It is given as $Workdone=Emf\times q$, where $q$ i.e. induced charge in a coil is independent of the time taken to charge the flux.
3. The work done is directly proportional to the emf.

When magnet is bought speedily:

1. When the magnet is bought speedily near the coil, the rate of change of flux will increase. So, the induced e.m.f will be higher.
2. Consequently, the work done will also be higher.

When magnet is bought slowly:

1. When magnet is bought slowly near the coil, the rate of change of flux will be low comparatively. So, the induced e.m.f will be lower.
2. Consequently, the work done will also be lower.

Hence,

1. The work done will be higher if the magnet is bought near the coil speedily.
2. The work done will be lower if the magnet is bought near the coil slowly.