#### fluidistic

Gold Member

- 3,585

- 77

**1. The problem statement, all variables and given/known data**

Show that the maximum intensity of 2 waves is worth [tex](E_{01}+E_{02})^2[/tex] while for 2 waves out of phase by pi rad, it's worth [tex](E_{01}-E_{02})^2[/tex].

**2. Relevant equations**

Not sure about intensity. According to my notes it's worth [tex](U_1+U_2)(U_1+U_2)*[/tex] where * denotes the complex conjugate. And [tex]U(x)=\sqrt{\frac{2}{\eta}}E(x)[/tex].

Also [tex]\eta=\frac{\sqrt{\frac{\mu _0}{\varepsilon _0}}}{n}[/tex] where n is the refractive index of the medium. Is there some easier formula for the intensity that I could use?

**3. The attempt at a solution**

As they don't say anything if the 2 waves have the same frequency, I think that indeed they have the same frequency otherwise it's senseless to talk of a phase. Am I right?