IB Physics SL C.3.4 Total Internal Reflection Question Bank

Practise IB Physics SL C.3.4 by checking both total-internal-reflection conditions, calculating critical angles and tracing rays in prisms and optical fibres.

[Maximum number: 2]

Monochromatic light enters the base of a plastic beaker that contains water with an oil layer floating on it. A student draws a diagram to show the directions the light takes as it passes through the layers. The student's diagram has one error at position A and one error at position B. The refractive indices of the materials are shown on the diagram.

Figure for Question C.3.4—Total internal reflection question 1 — IB Physics SL

The light is refracted at an angle of $32^{\circ}$ when it enters the plastic layer as shown.

Calculate the critical angle for the plastic-water interface.

$\begin{aligned} \frac{\sin i}{\sin r}=\frac{1.33}{1.60} \text { and } \sin r=1 i=\lessdot \sin ^{-1} 0.831 »=56<^{\circ} \gg \end{aligned}$

Accept 0.98 rad (unit required)

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C.3.4—Total internal reflection question 1