An observer can see through a pin-hole the top end of a thin rod of height h, placed as shown in the figure. The height of beaker is `3h` and its radius is h. When the beaker is filled with a liquid up to a height `2h`, he can see the lower end of the rod. Then the refractive index of the liquid is

Options

A. `5//2`
B. `sqrt((5//2))`
C. `sqrt((3//2))`
D. `3//2`

Answer

B

Explanation

`sini=(h)/(sqrt(h^2+(2h)^2))=1/sqrt5`
`musini=1xxsinr=1xxsin45^@`
`muxx1/sqrt5=1xx1/sqrt2impliesmu=sqrt(5/2)`