$(a)$ ચુંબક દાખલ થાય
$(b)$ ચુંબક અંદર હોય
$(c)$ ચુંબક બહાર આવે ત્યારે
When magnet is completely inside, flux will not change, so reading of galvanometer will be zero.
When bar magnet is making on exit, again flux will change and on e.m.f. is induced in opposite direction to not of \((a),\) so galvanometer will deflect in negative direction.