Q:
Two electric bulbs marked 25W – 220V and 100W – 220V are connected in series to a 440Vsupply. Which of the bulbs will fuse?
Answer & Explanation
Answer: A) 25 W
Explanation: Resistances of both the bulbs are
R1=V^2/P1 = 220^2/25
R2 = V^2/P2 = 220^2/100
Hence
When connected in series, the voltages divide in them in the ratio of their resistances. The voltage of 440 V devides in such a way that voltage across 25 w bulb will be more than 220 V. Hence 25 w bulb will fuse.
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