91影视

Snell's Law: It relates the refraction angle ${胃}_2$to the incident angle ${胃}_1$and the indexes of refraction of the incident medium n1and the refracted medium n2:

$n_1\sin 鈦�{胃}_1=n_2\sin 鈦�{胃}_2$

Angles of incidence and refraction are measured with respect to the normal line at the point where the ray intersects the interface between the two media. Medium 2 is more optically dense (has a higher refractive index) than medium 1 if the refracted ray is closer to the normal than the incident ray. In the same plane are the incident ray, refracted ray, and normal line.

The index of refraction of medium 1 is: n1

The index of refraction of medium 2 is:n2

We are asked to determine if n1 is larger than n2, n1 smaller than n2, or if there is not enough information to tell.

Let ${胃}_1$be the angle of the light ray with the normal to the surface of the medium and ${胃}_2$be the angle of the light ray with the normal the surface of the medium. Using this notation, we clearly see in the given figure that ${胃}_1>{胃}_2$which also means that $\sin {胃}_1>\sin {胃}_1$.

$\frac{\sin 鈦�{胃}_1}{\sin 鈦�{胃}_2}=\frac{n_2}{n_1}$

Hence, if $\sin {胃}_1>\sin {胃}_2,n_1$must be smaller than n2