A 25, W,220, V bulb and a 100, W,220, V bulb | vedclass

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(A) The resistance $R$ of a bulb is given by $R = V^2 / P$,where $V$ is the rated voltage and $P$ is the rated power.For the $25\, W$ bulb,$R_1 = (220

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$25\, W$ bulb

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(A) The resistance $R$ of a bulb is given by $R = V^2 / P$,where $V$ is the rated voltage and $P$ is the rated power.For the $25\, W$ bulb,$R_1 = (220)^2 / 25 = 1936\, \Omega$.For the $100\, W$ bulb,$R_2 = (220)^2 / 100 = 484\, \Omega$.When connected in series,the current $I$ flowing through both bulbs is the same.The brightness of a bulb is proportional to the power dissipated,given by $P_{dissipated} = I^2 R$.Since $R_1 > R_2$,the power dissipated in the $25\, W$ bulb is greater than that in the $100\, W$ bulb.Therefore,the $25\, W$ bulb will glow more brightly.

$A$ $25\, W$,$220\, V$ bulb and a $100\, W$,$220\, V$ bulb are connected in series across a $220\, V$ line. Which electric bulb will glow more brightly?

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