Light with intensity 20 W / `cm^2 ` is falling along the normal on a surface , which completely abssorbs the light area of the surface is 25 `cm^2 `
find the average force exerted y light on this surface in one hour .

Explanation

To solve the problem step by step, we will follow the process of calculating the average force exerted by light on the surface.

### Step 1: Calculate the Power of the Light
The intensity of the light is given as \( I = 20 \, \text{W/cm}^2 \) and the area of the surface is \( A = 25 \, \text{cm}^2 \).

Power \( P \) can be calculated using the formula:
\[
P = I \times A
...