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Interference

  • N1-11: DIFFRACTION SPECTRUM OF WHITE LIGHT - POINT SOURCE

    N1-11
    Demonstrate continuous spectrum.
    Light from a bright point source is focused by a condenser lens with iris and a 20 cm focal length cylindrical convex lens onto a slit. The slit is focused onto a distant screen by a 10 cm focal length convex spherical lens. The diffraction grating is placed in the beam following the 20 cm convex lens. The zero order white spot and several spectral orders can be seen on each side of the grating, as shown below. Gratings of 2000 lines/inch and 7500 lines/inch are presented with this demonstration; others are available on request.

    n1-11an1-11bn1-11c

  • N1-12: DIFFRACTION SPECTRA - GRATING ON OVERHEAD PROJECTOR

    N1-12
    Very simple white light diffraction spectrum.
    A slit is placed on the platform of the overhead projector, and a STAR grating is positioned on the upper exit lens of the projector. Filters or other transluscent slides can be placed on the slit to see their spectra on a screen.
    N1

    n1-12an1-12bn1-12c

  • N1-13: DIFFRACTION SPECTRUM OF WHITE LIGHT - PORTABLE

    N1-13
    Individual observation of white light spectrum.
    Hold a small (approximately 1" x 1 1/2") replica grating about an inch in front of your eye and look off to the side to see the spectrum. The gratings are cut from a roll of 13,200 line per inch replica grating material, and are very cheap, so they can be given to the students to keep as souveniers of their physics experience at the University of Maryland.

    n1-13a

  • N1-14: REFLECTION GRATING - LARGE

    N1-14
    Show a spectrum from a small bright source.
    Use the large reflection grating to obtain beautiful spectra from small bright sources. In the photograph at the left above the grating is being held in the beam, creating three orders of reflections. The zero order is a direct reflection (white) at the right of the photograph, while the second order spectrum can be seen to the left of the picture. The first order spectrum (center of picture) is washed out due to overexposure.
    N1, LS1

    n1-14a

  • N1-15:

    N1-15
    Simple white light diffraction spectrum for large spaces.
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    N1

  • N1-51: SPECTROMETER - HAND HELD

    N1-51
    Demonstrate spectra individually.
    This device uses a diffraction grating to create a spectrum. Hold the spectrometer up to your eye and aim it at the light to be analyzed. A calibration scale is contained in the device.