A glass beaker has diameter `4cm` wide at the bottom. An observer observes the edge of bottom when beaker is empty as shown in figure. When the beaker is completely filled with liquid of refractive index `n=sqrt(5//2)`, he can just see the centre of bottom, then the height of glass beaker is :

Options

A. `4 cm`
B. `sqrt(5//2) cm`
C. `16 cm`
D. None of these

Answer

A

Explanation

`sqrt((5)/(2)) sin i=1 sin e`
`rArr sqrt((5)/(2))(2 cm)/(sqrt(4 cm^(2)+h^(2)))=1 xx (4 cm)/(sqrt(16 cm^(2)+h^(2)))`
`rArr h=4 cm`.