6D20.15 - Gratings - Wavelength of a Laser

Code Number:
Demo Title:
Gratings - Wavelength of a Laser
Diffraction and Wavelength
Area of Study:
Optics, Astronomy
Different color lasers, slit plate, meter stick or meter tape measurer.

Some simple geometry will allow you to determine the wavelength of the laser light you shine through a single slit.  You will need to know the width of the slit, the distance from the slit to the screen, and the spacing between the spots that make up the interference pattern.  Use lasers of different colors if desired.

  • Dinh Xuan Khoa and Nguyen Huy Bang, "A Low-Cost Experimental Kit for Teaching Wave Optics Based on the CDIO Approach", TPT, Vol. 57, #3, Mar. 2019, p. 168.
  • David K. Walker, "Visible Diffracted Rays", TPT, Vol. 11, #7, Oct. 1973, p. 435, reprinted in TPT, Vol. 40, #3, Mar. 2002, p. 185.
  • Borislaw Bilash II and David Maiullo, "Bragging About Diffraction", A Demo a Day: A Year of Physics Demonstrations, p. 352.

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