Two electric heaters have power ratings P_1 and P_2, at voltage V. They are connected in series to a dc source of voltage V. Find the power consumed…

$\displaystyle R_{1}=\frac{V^{2}}{P_{1}}$ & $\displaystyle R_{2}=\frac{V^{2}}{P_{2}}$ $\displaystyle R_{e q}=R_{1}+R_{2}=V^{2}\left(\frac{1}{P_{1}}+\frac{1}{P_{2}}\right)$ $\displaystyle P_{\text {series }}=\frac{V^{2}}{R_{e q}}$ $\displaystyle P_{\text {series }}=\frac{V^{2}}{V^{2}\left(\dfrac{1}{P_{1}}+\dfrac{1}{P_{2}}\right)}$ $\displaystyle \frac{1}{P_{\text {series }}}=\frac{1}{P_{1}}+\frac{1}{P_{2}}$ No.