Q 12-06-125JEE MainJEE Main 2020 (4 Sep, Shift 1)Medium
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? The three positions are: (a) the magnet's entry, (b) magnet is completely inside and (c) magnet's exit.
Answer: (B) Dials (B)
(a) As the magnet enters, the flux through the coil increases: a current flows and the galvanometer deflects.
(b) While the magnet is well inside a long coil the flux is nearly constant: no deflection.
(c) As it leaves, the flux decreases: current in the opposite direction, so the deflection is to the other side. This is the sequence in (B).
Solution by Sreeraj P, M.Sc Physics