Question

The sun delivers ${10}^5{\text{W/m}}^2$ electromagnetic flux to the earth's surface. The total power that is incident on the roof of dimensions $(20\times 20){\text{m}}^2$ will be

• A. $2\times {10}^7\text{W}$
• B. ${10}^6\text{W}$
• C. $2\times {10}^6\text{W}$
• D. $4\times {10}^7\text{W}$

Answer 1

The correct option is D $4\times {10}^7\text{W}$

$\text{Power = Intensity × area}$
$={10}^5\times 400$
$=4\times {10}^7\text{W}$