A, B and C are three optical media of respective critical angles `C_1`, `C_2` and `C_3`. Total internal reflection of light can occur from A and B and also from B to C but not from C to A. Then the correct relation between critical angles is

Options

A. `C_1 gt C_2 gt C_3`
B. `C_1=C_2=C_3`
C. `C_3 gt C_1 gt C_2`
D. `C_1 lt C_2 lt C_3`

Answer

D

Explanation

T.I.R. can occur from A to B i.e. `mu_Agtmu_B`.
B to C i.e. `mu_Bgtmu_C`
`mu_Agtmu_Bgtmu_C`
`sinC=1/muimpliesmu=(1)/(sinC)`
`(1)/(sin C_1)gt(1)/(sinC_2)gt(1)/(sinC_3)`
`sinC_1 lt sinC_2 lt sinC_3`
`C_1 lt C_2 lt C_3`