# Beam of Light through a Prism

1. Apr 21, 2005

### DDV805

I think I posted my thread in the wrong section. Hopefully someone can help me get started with this problem please. Thanks a lot.

The figure is a right angle triangle with 30-60-90 degree angles (right angle).
The glass prism shown has an index of re-
fraction that depends on the wavelength of
the light that enters it. The index of refrac-
tion is 1.43 and wavelength 7.456 x 10^-7 in vacuum and 1.61 for light of wavelength 4.951 x 10^-7 m in vacuum. A beam of whitelight is incident from the left, perpendicular to the first surface, as shown in the figure,and is dispersed by the prism into its spectral components.Determine the speed of the 4.951x 10-7 mlight in the glass. Answer in units of m/s.
The figure is a right angle triangle with 30-60-90 degree angles (right angle).

--------------|30
--->----------|
--------------|
--------------|90___ _60__

2. Apr 22, 2005

### Claude Bile

If you know the index of refraction, the speed of the light inside the prism is just c/n.

Claude.