• # question_answer 26) A galvanometer is connected to the secondary coil. The galvanometer shows an instantaneous maximum deflection of 7 divisions when a current is started in the primary coil of the solenoid. Now, if the primary coil is rotated through $180{}^\circ C$, then the new instantaneous maximum deflection will be: A)  7 divisions,                B)  14 divisions.C)  0 divisions,                   D)  21 divisions.

When the coil is rotated through $180{}^\circ C$, the flux changes from $\Phi$to$-\Phi$ Hence change in flux is $\Phi -(-\Phi )=2\Phi .$Further $\Phi =Mi$ $\therefore$change in current =2i This cause a deflection of 14 divisions Hence, the correction option is [b].