A spider and a fly are on the surface of a glass sphere. As the fly moves on the surface, find the maximum area on the glass sphere for the spider to be able to see it? Assume that the radius of the sphere (R) is much larger than the sizes of the spider and the fly. take the refractive index of glass `mu_(g)` to be equal to `sqrt(2)`.

Answer

`2pi R^(2)`

Explanation

Sin c =`(1)/(mu) implies C = sin^(-1) .(1)/(sqrt(2)) = 45^(@)`

Required area as shown in figure = `(4piR^(2))/(2) = 2piR^(2)`