At what angle should a ray of light be incident on the face of a prism of refracting angle `60^(@)` so that it just suffers total internal reflection at the other face ? The refractive index of the material of the prism is 1.524.`

Explanation

`i_(1)=?, A=60^(@),mu=1.524`
`mu=(1)/(sinC)`
`C=r_(2)`
`sin C=sin r_(2)=(1)/(mu)=(1)/(1.524)=0.6561`
`r_(2)=41^(@)`
As `r_(1)+r_(2)=A`
`r_(1)=A-r_(2)=60^(@)-41^(@)=19^(@)`
`mu=(sin i_(1))/(sin r_(1))`
`sin i_(1)=1.524 sin 19^(@)`
`=1.524xx0.3256`
`=0.4962`
`i_(1)=29^(@)45^(1)`