# Disspersion homework help

1. Mar 29, 2012

### physgrl

1. The problem statement, all variables and given/known data
1. Light can be separated into its component colors by:

a. diffraction gratings

b. thin film interference

c. focusing a broad beam of light into a point

d. bends light as it passes the edge of an object

*e. both a and b

3. The attempt at a solution

I thought the answer was c because it seems like what happens in a prism, but apparently (answer key) its e. Can someone explain why? Thanks!

2. Mar 29, 2012

### tal444

Re: Disspersion

C, focusing a broad beam of light into a point is simply intensifying the light, kind of like using a magnifying glass to burn something. A prism slows down the wavelengths just enough so that the different wavelengths separate.

3. Mar 29, 2012

### physgrl

Re: Disspersion

ok but why do diffraction gratings separate the colors?

4. Mar 29, 2012

### tal444

Re: Disspersion

http://en.wikipedia.org/wiki/Diffraction_grating

From the article above: "In optics, a diffraction grating is an optical component with a periodic structure, which splits and diffracts light into several beams travelling in different directions. The directions of these beams depend on the spacing of the grating and the wavelength of the light so that the grating acts as the dispersive element."

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