(Solved): A laser beam is reflected by three parallel surfaces, as shown in the figure, How does the incident ...

A laser beam is reflected by three parallel surfaces, as shown in the figure, How does the incident angle \( \theta_{i} \) compare with the angle after the final reflection \( \theta_{f} \) ? \[ \begin{array}{l} \theta_{1}>\theta_{\mathrm{r}} \\ \theta_{i}<\theta_{f} \\ \theta_{i}=\theta_{f} \end{array} \]