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AB and CD are two slabs. The medium betw...

AB and CD are two slabs. The medium between the slabs has refractive index 2 . Find the minium angle of incidence of Q , so that the ray is totally reflected by both the slabs .

Text Solution

Verified by Experts

The correct Answer is:
`60^(@)`
Critical anglest at 1 and 2

`theta_(C_(1)) = sin^(-1)((mu_(1))/(mu_(2))) = sin^(-1)((1)/(sqrt2)) = 45^(@)`
`theta_(C_(2)) = sin^(-1)((mu_(3))/(mu_(2))) = sin^(-1)((sqrt3)/(2)) = 60^(@)`
Therefore , minimum angle of incidence for total internal reflection to take place on both slabs should be `60^(@)`
`i_("min") = 60^(@)`
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