Question

Lab 1: Snell's law and Refraction and Reflection

What properties of light change when leaving one transparent material and entering another?

Draw what it looks like when ripples move on top of water.

What is Huygens' Principle, and how do your circles above help visualize it?

What is Snell's Law, the equation?

What are the angles used in Snell's Law measured relative to?

If you go from a material of high index and then enter a low index material what happens to the angle the light makes?

Answer 1

When light travels from one transparent medium to the other, the wavelength and the speed of propagation changes.

The ripples produced are transverse to the direction of the propagation of the wave generated.

The Huygens-Fresnel principle states that every point on a wavefront is essentially a source of smaller wavelets. These wavelets spread radially outwards at the same speed as the primary wave. The new wavefront is a line/curve tangent to all of the wavelets. Here, the circles are the wavefronts.

The equation for Snell's law is:

where the angles are measured relative to the normal (which is perpendicular to the surface).

When light goes from a higher index region to a lower index region, it bends away from the normal which implies that the angle the light makes with the normal increases as compared to the angle it made in the higher index region.