Physics electric circuit mygod

The total current decreases but the current passes through the light bulb increases.

Because the resistance of the rheostat has increased, this forces more current to pass through the bulb than before (in a parallel arrangement, current tends to flow through the branch with small resistance). As a result, the current through the bulb becomes larger despite the decrease of the main current.

In the actual fact, this follows naturally from the increase in p.d. across the bulb. A higher p.d. drves more current to flow through the bulb than before.

O(a light bulb)+_____-O(a light bulb)+____-O(a light bulb)O(a light bulb)