The north pole of a magnet is brought down along the axis of a horizontal circular coil (figure). As a result, the flux through the coil changes from 0.35 weber to 0.85 weber in an interval of half a second. Find the average emf induced during this period. Is the induced current clockwise or anticlockwise as you look into the coil from the side of the magnet?
Given:
Initial flux 
Final flux 
Time interval 
Average induced emf in time interval Δt is given by
…(i)
Where
are flux across the cross section at time intervals 
respectively.
Putting the values in eqn.(i) we get,
Magnitude of induced emf =1V
From Lenz’s law,
The direction of induced current is such that it opposes the change that has induced it.
According to fig.
The flux in the downward direction increases, so the current is induced such that flux in upward direction increases. Therefore, current is induced in anticlockwise direction
Therefore, average emf induced in the coil is 1V in anti-clockwise direction