Question

1.160
24. Two bulbs take 2 A current at 50 V. They are joined in series and connected to a 120 V mains. Hon
much resistance will have to be connected in series with them so that current in each be 2 A ?​

Answer 1

Answer:

(1) Resistance of each bulb=V/I =50/2 = 25 Ohm

(2) Total resistance of two bulbs = 25+25=50 Ohm

(3) when they are connected in series with 120 V supply, current will be 120/50 = 2.4 amp.

(4)for getting current of 2amps , we need an additional Resistance in series with the circuit.

(5)So, V/ (R+Ra) = 2 amp

(6) 120/(50+Ra)= 2 amps or. 100+2Ra=120 or Ra=(120-100)/2=10 Ohms