Question

The electric bulb is markede10 W; 22 V. It is used for 10 hours daily for 30 days. Calculate the energy consumed by the bulb in joules and kWh?

Answer 1

$$\begin{gathered} \mathbf{Energy}\mathbf{}\mathbf{consumed}\mathbf{:} \\ \mathrm{E}=\mathrm{Pt} \\ =10\times 10\times 30 \\ =3000\mathrm{Wh} \\ \mathbf{=}\mathbf{3}\mathbf{}\mathbf{kwh} \\ =3\times 3.6\times {10}^6\mathrm{J} \\ \mathbf{}\mathbf{}\mathbf{}\mathbf{=}\mathbf{10}\mathbf{.}\mathbf{8}\mathbf{\times }{\mathbf{10}}^{\mathbf{6}}\mathbf{}\mathbf{J} \end{gathered}$$