A circular conducting loop is kept fixed in a region where a uniform magnetic field…
PHYSICS · Multi-part · A Level · Physics · Fields and their consequences · Fields and their consequences
Problem
A circular conducting loop is kept fixed in a region where a uniform magnetic field is directed normally into the plane of the loop. The magnitude of the field is gradually varied with time.
(i) State Faraday’s law of electromagnetic induction and write its mathematical form.
(ii) Explain with the help of Lenz’s law why the induced current in the loop must oppose the change in magnetic flux through it. What is the physical significance of the negative sign that appears in the mathematical form obtained in part (i)?
(iii) If the magnetic field through the loop is increased, indicate (with reason) the direction of the induced current as seen by an observer looking at the loop from the side of the incoming field. How will this direction change if the field is decreased instead?