### Sample Problem 1: Speed and Frequency
of Light Leaving an Optical Fiber

*Light moving from an optical fiber to air changes wavelength
from * 452nm *to * 633nm.

- A.
*What is the index of refraction of the fiber?*
- B.
*What is the speed of light in the fiber?*
- C.
*What is the frequency of the light in the fiber?*
- D.
*What is the frequency of the light in air?*

- A.
- Since we do not have five digits of accuracy in this problem, we can assume
that the wavelength of light in air,
_{air} = 633 nm is
the wavelength of the light in vacuum _{0}.

The index of refraction inside the fiber is 1.40.

- B.
- From the definition of
*n*, we have

The speed of light inside the fiber is 2.14 x 10^{8}m/s.

- C.
- Click for next step.

Copyright © 1999 Rensselaer Polytechnic Institute and DJ Wagner. All Rights Reserved.