As shown in the diagram, a ray of light incident on the surface of a parallel glass slab of thickness t and refractive index `5/4`. Ray emerges from the opposite face parallel toits initial direction but displaced sideways. Considering the incident angle `theta` to be very small, the displacement is given by `x=(t theta)/n`. Then the value of n is

Answer

`05.00`

Explanation

`(sinQ)/(sinr)=5/4`
`(theta)/r=5/4`
`r=(4Q)/5`
In `DeltaABC`
`sin(Q-r)~=(BC)/(AB)`
`:."sin"(theta)/5=(BC)/(AB)`
`BC=x=AB"sin"(theta)/5`
`x~~t"sin"(theta)/5~~(tQ)/5`
`n=5`