Answer & explanation
Correct answer: option 4
Refractive Index of glass w.r.t water is $n_{g,w} = \frac{n_g}{n_w} = \frac{5}{4}$
Critical angle $C = sin^{-1}\frac{1}{n_{g,w}} = sin^{-1}\frac{4}{5}$
Correct answer: option 4
Refractive Index of glass w.r.t water is $n_{g,w} = \frac{n_g}{n_w} = \frac{5}{4}$
Critical angle $C = sin^{-1}\frac{1}{n_{g,w}} = sin^{-1}\frac{4}{5}$