Experiment Description

Experiment

Experiment C03    Diffraction Grating with White Light Source

Objectives
  • Estimate the wavelength of light using a diffraction grating
  • Measure the angle of diffraction by simple geometry
  • Measure the angle of diffraction precisely by spectrometer
  • Learn the techniques in using a spectrometer
Description
In this activity, you will use a diffraction grating to form color spectrum of light from a filament lamp. You will measure the angle of diffraction to determine the wavelength of light. A spectrometer will be used to measure the angle more precisely.

In Experiment 1, you will use a metre rule to measure the separation between the first order image and apply simple geometry to find the angle of diffraction.

In Experiment 2, you will measure the angle of diffraction directly by a spectrometer.
Apparatus
metre rule [2]
set square [1]
clip [1]
diffraction grating (300 lines per mm) [1]
ray box with vertical filament [1]
12 V low voltage power supply [1]
long pin [2]
spectrometer [1]
laboratory jack [1]
color filter - red, green, blue [1 each]
sodium lamp [1]
Experiment