A) \[\sin \,\theta \,>\frac{3}{2}\]
B) \[\sin \,\theta \,>\frac{2}{3}\]
C) \[\sin \,\theta \,>\frac{8}{9}\]
D) \[\frac{2}{3}\sin \,\theta \,>\frac{8}{9}\]
Correct Answer: C
Solution :
Key Idea: There will be total internal reflection at face AC. The critical angle is the angle of incidence I the denser medium for which the angle of refraction in the rarer medium is 90°. From Snells law \[_{g}{{n}_{w}}=\frac{\sin C}{\sin {{90}^{o}}}\] \[\Rightarrow \] \[\sin C=\frac{_{a}{{n}_{w}}}{_{a}{{n}_{g}}}=\frac{4/3}{1.5}\] \[=\frac{8}{9}\] For total internal reflection \[\theta >C\]. \[\therefore \] \[\sin \theta >\frac{8}{9}\].You need to login to perform this action.
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