Answer to Question #162595 in Optics for Nama glory

Question

Calculate the critical angle for

(i) an air-glass surface

(ii) an air-water surface

(iii) a water-glass surface

Draw diagrams in each case illustrating the total reflection of a ray incident on the surface

Answer 1

Answer

i) the critical angle for an air-glass surface is given

$C'=sin^{-1}(\frac{1}{^a\mu _g}) \\=sin^{-1}(\frac{1}{1}) \\=90^°$

ii) the critical angle for an air-water surface is given

$C''=sin^{-1}(\frac{1}{^a\mu _w}) \\=sin^{-1}(\frac{1}{{1.33}})\\=48°44'$

iii) the critical angle for water-glass surface is given

$C'''=sin^{-1}(\frac{^a\mu _g}{^a\mu _w}) \\=sin^{-1}(\frac{1.55}{{1.33}})\\=62°27'$