Question

Study the circuit shown in which three identical bulbs B₁, B₂ and B₃ are connected in parallel with a battery of 4.5V

(i) What will happen to the glow of other two bulbs if the bulb B₃ gets fused ?

(ii) if the wattage of each bulb is 1.5 W how much reading will the ammeter A show when all the three bulbs glow simultaneously.

(iii) Find the total resistance of the circuit.

Answer 1

(i) Other bulbs will glow with the same brightness. 

(ii) When the bulbs are in parallel, wattage will be added (4.5 W) and the ammeter reading would be

I= P/V= 4.5 W/4.5V =1.0 Ampere

(iii) Since ammeter reading is 1.0 ampere, resistance of the combinatio., is 4.5/1.0 A=4.5Ω