Question

Calculate the speed of light in a medium, whose critical angle is 45${}^o$.

Answer 1

For critical angle we will use snell's law

C is critical angle and $C={45}^o$

$n_{medium}sinC=n_{air}sin90$ $n_{air}=1$

$sinC=\frac{1}{SinC}=\frac{1}{sin45}$

$n_{medium}=1.41$

we know that refractive index $n=\frac{speedoflightinvacuum}{speedoflightinmedium}$

where $c=3\times {10}^{8}m/s$

$1.414=\frac{c}{v}$

$v=\frac{3\times {10}^8}{1.414}$

$v=2.12\times {10}^{8}m/s$