1) The supply voltage in a room is 120 V. The resistance of the lead wires is 6 Ω. A 60 W bulb is already switched on. What is the decrease of voltage across the bulb, when a 240 W heater is switched on in parallel to the bulb? A) zero B) 2.9 V C) 13.3 V D) 10.04 V Answer: Option DExplanation:P=V2R R=120×12060=240 Ω Req = 240+6=246 Ω ⇒ i1=VReq=120246 v1=240246×120=117.073V ⇒ i2=12048+6 v2=4854×120=106.66V v1-v2= 10.04 V