GOALS
Physics
- Measure the index of refraction n of wax (or Lucite) for microwaves.
- Do some elementary interference studies and determine the wavelength of
the microwaves.
Technique
- Use angle-intensity measurements and apparatus symmetry to determine n
with high accuracy.
- Use many successive interference maxima and minima to find wavelengths in
material and in air with accuracies of a few percent.
- "Graphical extrapolation" should be employed in finding the phase
differences between interior and exterior reflection at dielectric
surfaces.
-
- Determine how accurately you can do angle and distance measurements and
use these errors to predict uncertainty in n and
.
- Determine 0 two ways and see if they agree within your
predicted errors.
Question (Work out in lab book before coming to class)
- If you know that the wavelength of the microwaves is 3 cm in air, then
when you change the thickness of the dielectric slab (Fig. 6) by 1 cm and
observe perpendicular reflected intensity changing from a maximum through a
minimum and back to a maximum, what is the value of the index of refraction of
the slab?
References
- Halliday and Resnick: 36-2, 37-4,5
- Bueche: 30.7, 31.3
- Lobkowicz and Melissinos (Vol II): 4.1, 2.1