| Optics >
Diffraction |
DCS# 6C10.12 |
SINGLE SLIT
PATTERN
APPARATUS
Cornell slitfilm plate
or adjustable slit
|
202-21-B5 |
| laser |
202-21-B6 |
DESCRIPTION
Shine the laser through the slits
on the plate to project interference patterns on a white board
or projection screen. The plate has single slits of
various widths, double slits of various widths and separations,
and sets of different numbers of multiple slits.
To smoothly vary the width of the slit, use the adjustable slit
(shown below) rather than the Cornell plate. If you want
to know the width of the slit, use the Cornell plate.
Green (532 nm) and red (650 nm) laser pointers can be used to
show the dependence of diffraction angle on wavelength.
NOTES
The layout
of the Cornell plate is shown here.
Column 1: single slits of
different widths
Column 2: double slits of
constant width and variable spacing becoming double slits of
constant spacing and variable width, becoming single slit of
varying width.
Column 3: gratings with
various ratios of slit width to slit spacing
Column 4: gratings with
different numbers of slits, each with same slit width and
spacing.
Column 5: double slits of
different spacings.
Refer to this
image for slit widths and spacings.
Beside each element:
top digit = number of lines,
middle
digit = width in points before 8x reduction,
bottom
digit = spacing in points between lines
(one point
= 0.013837 inch = 0.3523 mm).
The
distance in millimeters between the slits is shown under the
patterns.
