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

1) At a given point in space, the total light wave is composed of 3 phasors P1 = a, P2 = (a/2)e^(i(theta)), P3 = (a/2)e^(-i(theta)). What is the intensity of light at this point?

2. Relevant equations

3. The attempt at a solution

I solved it in the following way:

P = P1 + P2 + P3

= a + (a/2)e^(i(theta)) + (a/2)e^(-i(theta))

= a + (a/2)[cos(theta) + isin(theta) + cos(theta) - isin(theta)]

= a + acos(theta)

= 2acos^2(theta/2)

I = P^2

= 4a^2cos^4(theta/2)

But if P3 = ae^(-i(theta)) then this method won’t work, isn’t it? So could someone suggest a more general way to solve such problems?

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Intensity of light at a point

**Physics Forums | Science Articles, Homework Help, Discussion**