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Total internal reflection

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As shown, three light rays traveling inside glass are incident on the air-glass interface at an angle

θ = 55 °

.

The refractive index of glass for the three rays is given in the table below.

Rays	Refractive index
$1$ ‍	$n_{1} = 1.15$ ‍
$2$ ‍	$n_{2} = 1.20$ ‍
$3$ ‍	$n_{3} = 1.25$ ‍

Which ray(s) will escape from glass to air?

Stuck?

Stuck?