Physics Demonstrations
Department of Physics and Astronomy
Physics Demonstrations

Light Intensity Relative to Spectrum

Identifier: Astro - 006

A lamp with no shade is connected to a power stat next to a box of diffraction gratings

Concept Overview:

The spectrum emitted by a light source is independent of the intensity of the light.  Although brighter or dimmer, the wavelengths produced will remain the same.

Instructor Procedure

Step(s) to FollowExpected Result
  1. Turn on Power Stat.
  2. Ask students to look through the diffraction grating at the light.
They will see a continuous emission spectrum.
  1. Adjust the dial on the power stat.
The light bulb will grow brighter or dimmer.  They will see a continuous emission spectrum, but it will grow either brighter or dimmer as the light source does.

 

Tutorial: Set-up Instructions for Astro - 6

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