A 100 W lamp and a 500 W room heater are connected to the same 220 V supply in parallel
PHYSICS · Single correct · AP · Physics 2: Algebra-based · Electric Circuits · Electric Circuits
Problem
A 100 W lamp and a 500 W room heater are connected to the same 220 V supply in parallel. If the heater is switched off, what happens to the brightness of the lamp?
(a) It becomes brighter because the current through the lamp increases when the total circuit current decreases.
(b) It becomes dimmer because the supply voltage across it drops when the heater is disconnected.
(c) It remains unchanged.
(d) It goes off because switching off the heater opens the entire circuit.