Question

Dan confirms the authenticity of an amethyst stone by a few tests. During one of the tests, he finds the angle of the refracted ray of light coming out of the amethyst into the air as 28°. If the refractive index of amethyst is 1.55, what is the incident angle?

A) 152
B) 26
C) 47
D) 72

Answer 1

C.47
by Snell's law\[\frac{ \sin \theta _{1} }{ \sin \theta _{2} }=\frac{ \eta _{1} }{ \eta _{2} }\]
\[\sin \theta _{2}=\sin \theta _{1}\times \frac{ \eta _{1} }{ \eta _{2} }\]
\[\sin \theta _{2}=\sin 28\times \frac{ 1.55 }{ 1 }\]
if we solve this we get around 46.69 i.e. 47.