Lenz's Law, Eddy Currents & Induced Electric Field
A small bar magnet is moved through a coil at constant speed from one end to the other. Which of the following series of observations will be seen on the galvanometer G attached across the coil?
Three positions shown describe:
(a) the magnet's entry
(b) magnet is completely inside and
(c) magnet's exit.
Show answer and solution
Answer: (c)
- Entry: flux through the coil increases, so G deflects one way.
- Fully inside (small magnet in a long coil): flux nearly constant, so no deflection.
- Exit: flux decreases, so G deflects the opposite way.
- This matches (c): deflection, zero, opposite deflection.