Q. 145.0( 1 Vote )

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?

Answer :


Initial flux

Final flux

Time interval

Average induced emf in time interval Δt is given by



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

Rate this question :

How useful is this solution?
We strive to provide quality solutions. Please rate us to serve you better.
Related Videos
Electromagnetic InductionElectromagnetic InductionElectromagnetic Induction50 mins
Source of Electromagnetic waveSource of Electromagnetic waveSource of Electromagnetic wave6 mins
Try our Mini CourseMaster Important Topics in 7 DaysLearn from IITians, NITians, Doctors & Academic Experts
Dedicated counsellor for each student
24X7 Doubt Resolution
Daily Report Card
Detailed Performance Evaluation
view all courses