What will be the minimum angle of incidence such that the total internal reflection occurs on both the surfaces?

What will be the minimum angle of incidence such that the total intern

1.	What will be the minimum angle of incidence such that the total internal reflection occurs on both the surfaces?
Answer» Solution :Critical angle at `A=C_1` `therefore sin C_1=mu_1/mu_2=sqrt2/2=1/sqrt2, C_1=45^@` Critical angle at `B=C_2` `therefore sinC_2=mu_3/mu_2=sqrt3/2 therefore C_2=60^@` `therefore` Minimum angle of incidence for TOTAL internal REFLECTION to occur on both the slabs should be `60^@` `therefore i_min=60^@`