We can solve the problem by using Snell's law, which states
[tex]n_i \sin \theta_i = n_r \sin \theta_r[/tex]
where
[tex]n_i[/tex] is the refractive index of the first medium
[tex]\theta_i[/tex] is the angle of incidence
[tex]n_r[/tex] is the refractive index of the second medium
[tex]\theta_r[/tex] is the angle of refraction
In our problem, [tex]n_i=1.00[/tex] (refractive index of air), [tex]\theta_i = 28.0^{\circ}[/tex] and [tex]n_r=1.63[/tex] (refractive index of carbon disulfide), therefore we can re-arrange the previous equation to calculate the angle of refraction:
[tex]\sin \theta_r = \frac{n_i}{n_r} \sin \theta_r = \frac{1.00}{1.63} \sin 28.0^{\circ} = 0.288[/tex]
From which we find
[tex]\theta_r = \arcsin (0.288)=16.7^{\circ}[/tex]
