Question

1. fill in the missing angle

surface
$\theta_1 = \boxed{32^\circ}$
$\theta_1 = $ angle of incidence

Explanation:

Step1: Recall the law of reflection

In the law of reflection, the angle of incidence ($\theta_i$) is equal to the angle of reflection ($\theta_r$).

Step2: Apply the law to the given problem

Here, the angle of incidence ($\theta_1$) is given as $32^\circ$. So, the angle of reflection (the missing angle) should be equal to the angle of incidence.

Answer:

$32^\circ$