Two Bulbs Are Marked 100 W, 220 V and 60 W, 110 V. Calculate the Ratio of Their Resistances. - Physics

Two bulbs are marked 100 W, 220 V and 60 W, 110 V. Calculate the ratio of their resistances.

Answer in Brief

Given I^st Bulb

P₁ = 100 W

V₁ = 220 V

II^nd Bulb

P₂ = 60 W

V₂ = 110V

We know P = `"V"^2/"R"`

So R = `"V"^2/"P"`

So `"R"_1/"R"_2 = ("V"_1^2/"P"_1)/("V"_2^2/"P"_2)`

`= ("V"_1^2 xx "P"_2)/("P"_1 xx "V"_2^2)`

`= (220^2 xx 60)/(100 xx 110 xx 110) = 2.4`

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