TBR Snell's Law

[redbird1133]

Advertisement - Members don't see this ad

In TBR section 10, number 34 says: which of these images are consistent with Snell's law?
(Image attached)
I guess I'm pretty much confused on what "normal" is. The book states that III and IV travel along the normal, what does that mean? Because I and III look the same to me other than that the middle arrow is sloped down on I.
Thanks!

 

[justadream]

@redbird1133

Normal means perpendicular to the surface. Draw a line perpendicular to the surface (in this case, that would be a horizontal line).

It looks like the index of refraction of the block is greater than that of air.

Thus, when light enters the surface, it bends TOWARD the normal (going from smaller to larger index).

When light leaves the surface, it bends AWAY from the normal (going from larger to smaller index)

 

[redbird1133]

@redbird1133

Normal means perpendicular to the surface. Draw a line perpendicular to the surface (in this case, that would be a horizontal line).

It looks like the index of refraction of the block is greater than that of air.

Thus, when light enters the surface, it bends TOWARD the normal (going from smaller to larger index).

When light leaves the surface, it bends AWAY from the normal (going from larger to smaller index)

Thank you for the explanation!