Question

Light is incident normally on face AB of a prism as shown in Figure. A liquid of refractive index `mu` is placed on face AC of the prism. The prism is made of glass of refractive indes `3//2` . Find the limits of `mu` for which total internal reflection takes place on the face AC.

A. `mule(3sqrt3)/(4)`
B. `mu gt sqrt(5/2)`
C. `mu gt sqrt2`
D. `mu lt sqrt3`

Answer 1

Correct Answer - A

Critical angle for glass-liquid
`._amu_gsinC=._amu_lsin90^@`
`3/2sinC=mu`
`sinC=(2mu)/(3)`
For T.I.R. on AC
`60^@geC`
`sin60^@gesinC`
`sqrt3/2 ge(2mu)/(3)`
`(3sqrt3)/(4) gemu`
`mule(3sqrt3)/(4)`