A light ray enters a rectangular block of plastic at an angle of ${}_1=44\mathrm{.}0$ and emerges at an angle of ${}_2=75\mathrm{.}5$ as shown in the figure below.

$($i$)$

$($a$)$ Determine the index of refraction of the plastic.

What is the relationship betwaen the angle of refraction at the vertical interface and the angle of incidence at the horizontal interface?

$($b$)$ If the light ray enters the plastic at a point $L=50\mathrm{.}0cm$ from the bottom edge, what time interval is required for the light ray to travel through the plastic?

What is the length of the path traveled by the light inside the plastic block? ns

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