NEET-XII-Physics
qstns with ansrs year:2022
- #44Two transparent media `` A `` and `` B `` are separated by a plane boundary. The speed of light in those media are `` 1.5 \times 10^{8} m / s `` and `` 2.0 \times 10^{8} m / s `` , respectively The critical angle for a ray of light for these two media is :
(A) `` \tan ^{-1}(0.750) ``
(B) `` \sin ^{-1}(0.500) ``
(C) `` \sin ^{-1}(0.750) ``
(D) `` \tan ^{-1}(0.500) ``digAnsr: CAns : `` \mu=\frac{ C }{ u } \Rightarrow u \propto \frac{1}{\mu} ``
Critical angle
`` \operatorname{Sini}_{ c }=\frac{\mu_{ R }}{\mu_{ D }}=\frac{ u _{ D }}{ u _{ R }}=\frac{1.5}{2}=\frac{3}{4} ``
`` i _{ c }=\sin ^{-1}\left(\frac{3}{4}\right) ``
`` \sin \dot{i}_{ c }=\frac{\mu_{ R }}{\mu_{ D }}=\frac{ u _{ D }}{ u _{ R }} ``
`` i _{ c }=\sin ^{-1}\left(\frac{3}{4}\right) ``