Answer:
[tex]\mu=41.5\textdegree[/tex]
Explanation:
From the question we are told that:
Water index of refraction [tex]i_w=1.33[/tex]
Glass index of refraction [tex]i_g=1.50[/tex]
Generally the equation for Brewster's law is mathematically given by
 [tex]\theta=tan^{-1}(\frac{i_g}{i_w})[/tex]
 [tex]\theta=tan^{-1}(\frac{1.50}{1.33})[/tex]
 [tex]\theta=48.44 \textdegree[/tex]
Therefore Angle of incident to plane  \mu (normal at 90 degree to the surface)
 [tex]\mu=90\textdegree-\theta[/tex]
 [tex]\mu=90\textdegree-48.44\textdegree[/tex]
 [tex]\mu=41.5\textdegree[/tex]
