If 25W, 220 V and 100 W, 220 V bulbs are connected in series

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If 25W, 220 V and 100 W, 220 V bulbs are connected in series across a 440 V line, then

1. only 25W bulb will fuse
2. only 100W bulb will fuse
3. both bulbs will fuse
4. none of these

Correct Option: A

As for an electric appliance R = (V_s² / W),so for same specified voltage V_s

	R₂₅	=	100	= 4
	R₁₀₀		25

i.e, R₂₅ = 4R with R₁₀₀ = R
Now in series potential divides in proportion to resistance.
So, V₁ = (R₁/R₁ + R₂)V
i.e., V₂₅ = (4/5) x 400 = 352 V
and V₂ = (R₁/R₁ + R₂)V
i.e., V₁₀₀ = (1/5) x 400 = 88V
From this, it is clear that voltage across 100 W bulb (= 88 V) is lesser than specified(220 V) while across 25 W bulb (= 352 V) is greater than specified (220 V), so, 25 W bulb will fuse.