Answer:
[tex]\theta_i = 23^o[/tex]
Explanation:
The refractive index of a medium is given by the following formula:
[tex]\eta = \frac{Sin\theta_i}{Sin\theta_r}[/tex]
where,
η = refractive index = 1.5
[tex]\theta_i[/tex] = angle of incidence = ?
[tex]\theta_r[/tex] = angle of refraction = 15°
Therefore,
[tex]1.5 = \frac{Sin\theta_i}{Sin15^o}\\\\Sin\theta_i=(1.5)Sin15^o\\\\\theta_i = Sin^{-1}(0.388)\\\\[/tex]
[tex]\theta_i = 23^o[/tex]
