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Question
The diagram below shows a light source P embedded in a rectangular glass block ABCD of critical angle 42°. Complete the path of the ray PQ till it emerges out of the block. [Write necessary angles].
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Solution
Given, critical angle, C = 42°
At a point Q, i = 48° and iC = 42°
i.e. i > iC
r = 48°
At a point P, i = 42° and iC = 42°
i = iC
Therefore, r = 90°
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