The Index of Refraction of Water for Short Continuous Waves
Abstract
The index of refraction of water for short continuous waves (300 to 700 cm) was measured from the phase difference resulting between two portions of a wave, one portion of which had passed through the dielectric. The phase difference was detected and measured by the rotation of the Lissajous figure, formed on the screen of a cathode ray oscillograph, due to the simultaneous action on the cathode beam of two tuned circuits receiving the two portions of the wave. The two circuits were attached to the opposite pairs of deflector plates of the oscillograph. The index of refraction was calculated from the relation μ=mλd+1, where λ is the wave-length, d the thickness of interventing dielectric in one path, and m the fraction of a period by which the wave passing through the dielectric is retarded relative to the one passing through air. The results are in good agreement with the electrical refractive index found by other methods, i.e., about 9, and approximately constant over the range of frequencies used. Brief reference is made to a method by which it is hoped to measure the dielectric constant under conditions identical with those existing in the measurement of the index of refraction, to be used in conjunction with the latter, in testing Maxwell's relation between index of refraction and dielectric constant.
- Publication:
-
Physical Review
- Pub Date:
- June 1927
- DOI:
- 10.1103/PhysRev.29.880
- Bibcode:
- 1927PhRv...29..880M