A parallel beam of uniform, monochromatic light of wavelength 6600 Å has an intensity of `900 Wm^(-2)`. The number of photons in `1 mm^2` of this radiation are `1xx 10^(X)` then find out value of X.

Explanation

To solve the problem, we need to find the number of photons in a 1 mm² area of the given light radiation. We will follow these steps:

### Step 1: Understand the given data
- Wavelength of light, \( \lambda = 6600 \, \text{Å} = 6600 \times 10^{-10} \, \text{m} \)
- Intensity of light, \( I = 900 \, \text{W/m}^2 \)
- Area of interest, \( A = 1 \, \text{mm}^2 = 1 \times 10^{-6} \, \text{m}^2 \)

### Step 2: Calculate the energy incident on 1 m² in 1 second
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