Rami Arieli: "The
Laser Adventure" Snell's Law Applet
Snell's Law Applet
This simulation can help you see what
happens to a light beam when it goes from one medium into another.
The light beam is refracted according to Snell's
If the index
of refraction of the medium where the beam
comes is greater than the index of refraction of the other medium, there
exists a critical angle.
For angles greater than the critical angle, the wave is reflected
back with the same angle as the incident angle. This phenomena is called:
"Total Internal Reflection".
In this applet you can change
the indices of refraction, and the
incident angle as you like, and watch the result.
Choose an index of refraction of the beam origin higher
than the index of refraction of the other medium.
Change the incidence angle,
and check what happened to the refracted
Is the refracted angle bigger/Smaller
than the incidence angle?
How does your answer agree with Snell's
Since the angles are measured to
the perpendicular to the boundary surface, does the refracted
beam approach the perpendicular, or further away from it?
The table lists the index
of refraction of some common materials:
Change the incidence angle, and check what happened to the refractive
What happened when the value of the incidence angle is higher than some
The minimum value of the incidence angle that cause this is called
What is the critical angle when a beam of light pass from water to air?
The index of refraction of a fiber optic glass is 1.52.
What is the minimum angle at the entrance of a streight fiber, such
that the light will stay within the fiber, and exit from the other end
(as seen on the figure)?
Figure 1: Light confined to the optical fiber.