Question:
I am doing a practical experiment and am required to
design a laboratory experiment using a LDR to investigate how the
intensity of light emitted by a lamp varies with wavelength. I am
wondering what the best way of altering the wavelength of light is
in a school laboratory. I was thinking either a prism or coloured
filters.. but then how would I MEASURE the wavelength of the light?
Replies:
Charlotte,
Most glass has not one index of refraction but a range for visible
light. Usually violet has the greatest index and red has the least. If
you wish to use a prism, laws of refraction can tell you at which angle
each wavelength will project. You will need a fairly precise set of
indices of refraction. I suggest contacting the company that makes the
prism. Such a company may even be able to tell you which of their
prisms have the greatest range of indices. Quite often the producer of
equipment can be a valuable source of information.
Dr. Ken Mellendorf
Physics Instructor
Illinois Central College
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