a square loop initially kept away from the region of magnetic field .then it is moved towards the right with a constant velocity and goes out of the field.plot the graph showing the variation of

1)magnetic flux through the loop with time

2)induced emf in the loop with time

 

When the loop is far away from magnetic field, flux is zero. when the loop entering the magnetic field region, flux increases from zero

to a constant value, then remains constant when it is moving in the field region. During exit time, the flux decreases from constant value to zero.

 

Induced emf is given by

, where ε is induced emf and φ is flux

When the loop is far away, the flux is zero and emf also zero. When the loop entering field region, the change in flux gives induced emf.

At the entrance change in flux is positive, hence induced emf is negative.

when the loop is well inside the field region, since flux remains constant, change in flux is zero, hence emf also zero.

when loop is exiting the field region again change in flux gives induced emf. Here change in flux is negative, hence induced emf is positive.