Light with an energy flux of `18 W cm^(-2)` falls on a non-reflecting surface at normal incidence. If the surface at normal incidence. If the surface has an area of `20 cm^(2)`, find the average force exerted on the surface during a span of 30 min.

Explanation

To solve the problem step by step, we will follow these calculations:

### Step 1: Understand the given values
- Energy flux (intensity) \( I = 18 \, \text{W/cm}^2 \)
- Area of the surface \( A = 20 \, \text{cm}^2 \)
- Time duration \( T = 30 \, \text{min} = 30 \times 60 \, \text{s} = 1800 \, \text{s} \)

### Step 2: Convert the area to square meters
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