Question

answer it fast plz plz plz​

Answer 1

When the switch is off the circuit is in series combination. Since in series combination the current remains same the brightness of the bulb remains same.

But when the switch is on the lamps Q and R become parallel. As a result the current which is flowing to Lamp Q gets divided. But the current after passing to the lamps Q and R gets in series combination. So the lamp P remains to glow with same brightness whereas the brightness of the lamp Q decrease since the current is getting reduced..

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