Question

The Sun delivers ${10}^{3}W/m^2$ of electromagnetic flux to the Earth's surface.The total power that is incident on a roof of dimensions $8m\times 20m$, will be

• A. $6.4\times {10}^{3}W$
• B. $3.4\times {10}^{4}W$
• C. $1.6\times {10}^{5}W$
• D. none of these

Answer 1

The correct option is C $1.6\times {10}^{5}W$

Here the power per unit area is given, $I={10}^{3}W/m^2$

So, the total power $=I\times$ area of roof $={10}^3\times (8\times 20)=1.6\times {10}^{5}W$