4 bulbs marked 40, W, 250, V are connected in | vedclass

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(A) The rated power of each bulb is $P = 40\, W$ at a rated voltage of $V = 250\, V$.The resistance of each bulb is given by $R = \frac{V^2}{P} = \fra

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$10$

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(A) The rated power of each bulb is $P = 40\, W$ at a rated voltage of $V = 250\, V$.The resistance of each bulb is given by $R = \frac{V^2}{P} = \frac{250^2}{40} = \frac{62500}{40} = 1562.5\, \Omega$.When $n = 4$ identical bulbs are connected in series,the total resistance is $R_{eq} = nR = 4 	imes 1562.5 = 6250\, \Omega$.The total power consumed by the series combination connected to the $250\, V$ mains is $P_{total} = \frac{V^2}{R_{eq}} = \frac{250^2}{6250} = \frac{62500}{6250} = 10\, W$.Alternatively,for $n$ identical bulbs in series,the total power is $P_{total} = \frac{P}{n} = \frac{40}{4} = 10\, W$.

$4$ bulbs marked $40\, W, 250\, V$ are connected in series with a $250\, V$ mains. The total power consumed is ............. $W$.

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