In the network shown, initially the switch S is open. Then just after the switch S is closed, brightness of the bulb

Before S is closed, magnetic flux linked with the inductor = LiAfter S  is closed, Le=L x LL+L=L2So magnetic flux =  L2i'By Lenz's law, L2i'=Li⇒i'=2iSince just after S is closed the current is doubled, so brightness increases