InterviewSolution
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InterviewSolution
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A fish in a water tank sees the outside world as if it (the fish) is at the vertex of cone such that the circular base of the cone coincides with the surface of water. Given the depth of water where fish is located being h and the critical angle for water-air interface being ic, find out by drawing a suitable ray diagram the relationship between the radius of the cone and the height h. |
Answer» Solution :The ray diagram is shown in Fig. 9.41. Here B is a FISH SITUATED at a depth from the WATER surface and R is the radius of the cone. By definition of critical angle, we have: `sin i_( C) =1/n`, where n is the refractive index of water  But, `sin i_( C) = (CA)/(BA) = R/sqrt(R^(2) + H^(2))` Hence, `1/n = R/sqrt(R^(2) + h^(2)) rArr R =h/sqrt(n^(2)-1)` |
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