Answer
three
Work Step by Step
We will be finding our wavelengths, $\lambda$, using the conditions for constructive interference (equation 35-37):
$2L=m \lambda /n_2$ (for $m=0,1,2,3$)
Solving for $\lambda$, we obtain:
$\lambda=2*n_2*L/m $
$\lambda=2*1.40*600nm/m $
$\lambda_i=2*1.40*600nm/m_i $
Therefore;
$\lambda_1=2*1.40*600nm/(1) = 1680nm$
$\lambda_2=2*1.40*600nm/(2) = 840nm$
$\lambda_3=2*1.40*600nm/(3) = 560nm$
$\lambda_4=2*1.40*600nm/(4) = 420nm$
$\lambda_5=2*1.40*600nm/(5) = 336nm$
We see that we have three different wavelengths that are between 300 and 700nm.
