a glass prism with respective index 1.5 is immersed in water (refractive index 4/3 ). a light beam incident normally on the face AB is totally reflected to reach the face BC if
(a) sin θ >8/9 (b)2/3 < sin θ < 8/9
(c)sin θ < 2/3 (d)none of these
answer is a
plz give sol..
1Let ∂c be the critical angle at face AC ,
then sin ∂c = uw / ug =( 4/3 ) / (3/2) = 8/9 .
angle of incidence at face AC is i = ∂ .
total internal reflection will take place on dis surface if,
i>∂c or
∂>∂c or
sin ∂ > sin ∂c or
sin ∂ > 8/9 . I THINK ITS OPTION A [1]
i have taken theta as ∂
1oops .. u do one thing .. drop da ray perpendicular to da surface AB and EXTEND it to AC .. see i think it makes angle theta .... not 90-theta [1]
