Slit
View Finder &
Diffraction grating
(500 lines/mm)
Scale
A line with 400nm would be:
-9
(1)(400 x10 m)(0.19m)
y = = 0.038m or 3.8 cm
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2.0 x 10 m
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(1)(700 x10 m)(0.19m)
y = = 0.067m or 6.7 cm
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2.0 x 10 m
The value for d is determined by the diffraction grating. If there are
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500 lines/mm, then there are 2.0 x 10 m between the slits.
REQUIRED COMPONENTS (NOT INCLUDED)
Name of Part Quantity
Light Source from a fluorescent light bulb 1
RECOMMENDED COMPONENTS (NOT INCLUDED)
Name of Part Quantity
Spectrum Tube Power Supply
(with safety door) PH 1199B (110V) 1
Spectrum Tubes Assorted
(O, Ne, He, N, Ar, CO2, H, I, S, Xe, Kr)
PH 1196B 1-111
Spectrum Chart 1
DIAGRAM LABELING ALL PARTS:
A line with 700nm would be:
GENERAL BACK GROUND:
A spectroscope helps scientist (and you) to study and observe a
spectrum of light. In this case it helps you to observe visible light.
Visible light is just part of the electromagnetic spectrum. What
makes this band of light unique is that humans can detect these
frequencies with their eyes. There are other animals like bees for
example that are able to see different frequencies of light. Scientists
also use spectroscopes to study ultraviolet and infrared spectrums
of faraway stars and galaxies. They can use these spectrums to
determine the elements burning in distant stars.
When white light travels from one medium to another such as from air
to glass, the light slows down and bends. The frequency of the light
determines how much the light bends. Therefore shining white light
through a prism will sort the light by its frequency. The higher the
frequency of light the more it bends. This is called dispersion of light.
Many spectroscopes use a prism to separate white light into its
spectrum. However this spectroscope uses a diffraction grating.
Similarly, when white light travels through a double slit, an
interference pattern immerges that is dependent on the wavelength
of light. A diffraction grating will also reveal a spectrum. In this case
the diffraction grating has a series of parallel slits 500 lines/mm. The
distance from the slit to the diffraction grating is approximately 19cm
or 0.19m.
mlL ,
Using the formula y =
d
where y is the distance between the center bright fringe and the fringe
you are looking at and m is an integer ordering each maximum bright
point, and l is the wavelength of light, we can calculate where a red
line and violet line would be positioned on the end of the
spectroscope.
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© EISCO SCIENTIFIC ● www.eiscosci.com
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© EISCO SCIENTIFIC ● www.eiscosci.com
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