(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Red and green laser (wavelength of 650 nm and 532 nm respectively) are directed towards each other at 20 degrees.

Each laser has 5 mW power, with diameter of 1mm.

Assuming the intensity of the beams are decreased by 10% each after the 'collision',

estimate the upper limit on the cross section, σ, for the scattering.

2. Relevant equations

σ = 0.1*(N_{RED}+ N_{GREEN}) / (N_{RED}+ N_{GREEN})*π*0.0005^2

where N is the number of photons per second

N = 5e-3 / (hc/λ)

3. The attempt at a solution

I'm just unsure whether the equation I used for σ is correct or not.

Can somebody confirm?

Many thanks in advance!

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# Homework Help: Cross section - scattering of light by light

Can you offer guidance or do you also need help?

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