The angle between any two lines is equal to the angle between their perpendiculars.
$\therefore i=30^{\circ}$
From Snell's law, we have
$ \frac{1}{1.5}=\frac{\sin 30^{\circ}}{\sin r} $
$ \Rightarrow \sin r=0.75 \text { or } r=48.6^{\circ}$
Therefore, $\theta=r-i$
$=48.6^{\circ}-30^{\circ}=18.6^{\circ}$
$\therefore$ Required angle between two emergent rays
$ =2 \times 18.6^{\circ}$
$ =37.2^{\circ} C \approx 37^{\circ}$
