Q.
Three identical coils $A,\ B\ and\ C$ are placed with their planes parallel to one another. Coils $A\ and\ C$ carry currents as shown in figure. Coils $B\ and\ C$ are fixed in position and coil A is moved towards $B$. Then, current induced in $B$ is in
A) Clock-wise current
B) Anti-clock-wise current
C) No current is induced in $B$
D) Current in induced only when both coils move
Explanation
(b) As coil $A$ is moved closer to $B$, field due to $A\ intercepting\ B$ is increasing. Induced current in $B$ must oppose this increase. Hence the current in $B$ must be anti-clock-wise.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.