A ray of light propagates from glass (refractive index =(3/2) ) to water (refractive index .=(4/3)). The value of the critical angle is.

Question

A ray of light propagates from glass (refractive index =(3/2) ) to water (refractive index .=(4/3)). The value of the critical angle is. (A)  sin -1((1/2)) (B)  sin -1(√(9/8)) (C)  sin -1((8/9)) (D)  sin -1((5/7))

Tardigrade Admin · Accepted Answer

The angle of incidence in denser medium for which the angle of refraction in rarer medium is

9 0^{\circ}

is called the critical angle

(C)

.

μ_{w}

and

μ_{g}

are refractive indices for rarer (water) and denser (glass) media, then

\frac{s i n C}{s i n 9 0 ^{\circ}} = \frac{μ _{w}}{μ _{g}}

\Rightarrow sin C = \frac{4/3}{3/2} = \frac{8}{9}

\Rightarrow C = sin^{- 1} (\frac{8}{9})

Note : The critical angle for water-air, glass-air and diamond-air interfaces are

4 9^{\circ}, 4 2^{\circ}

and

2 4^{\circ}

, respectively.

Q. A ray of light propagates from glass (refractive index $= \frac{3}{2}$ ) to water (refractive index $= \frac{4}{3})$ . The value of the critical angle is.

$sin^{- 1} (\frac{1}{2})$

$sin^{- 1} (\frac{9}{8})$

$sin^{- 1} (\frac{8}{9})$

$sin^{- 1} (\frac{5}{7})$

Q. A ray of light propagates from glass (refractive index =23​ ) to water (refractive index =34​). The value of the critical angle is.

sin−1(21​)

sin−1(89​​)

sin−1(98​)

sin−1(75​)

Q. A ray of light propagates from glass (refractive index $= \frac{3}{2}$ ) to water (refractive index $= \frac{4}{3})$ . The value of the critical angle is.

$sin^{- 1} (\frac{1}{2})$

$sin^{- 1} (\frac{9}{8})$

$sin^{- 1} (\frac{8}{9})$

$sin^{- 1} (\frac{5}{7})$