Poll Results
No votes. Be the first one to vote.
If two bulbs of wattage 25 W and 100 W respecti-vely each rated at 220 V connected in series with the supply of 440 V, which bulb will fuse?
Resistance of a bulb is
R = V²/P . For 25 W:
R₁ = 220²/25 = 1936Ω and for 100 W:
R₂ = 220²/100 = 484Ω.
Total resistance Rtotal = 1936 + 484 = 2420Ω.
Current I = 440/2420 = 0.1818 A.
Voltage across 25 W bulb: V₁ = IR₁ = 0.1818 × 1936 = 352 V (exceed 220 V, so it fuses).
Answer: (a) 25 W bulb.
Share