Physics - Current Electricity Question with Solution | TestHub

Let$R$be the resistance of each bulb.

We have$P=\frac{V^2}{R}$

or$R=\frac{V^2}{P}=\frac{V^2}{100}$

When the bulbs are connected in series, the voltage across each of them is . Hence, the total power consumed is

$P^{\prime }=\frac{{\left( \frac{V}{2}\right)}^2}{R}+\frac{{\left( \frac{V}{2}\right)}^2}{R}=\frac{V^2}{2R}$

${\therefore P}^{\prime }=\frac{P}{2}=\frac{100}{2}=$$50 \mathrm{W}$