Ma Be wrote in USMA 19351:
>Yesterday I was browsing through their recent reports concerning this
>change and discovered that they apparently are facing some dilemmas on
>this, and I gather (and am somewhat "relieved" and taking solace) that
>they are cognizant of my position since they seem to continue to consider
>that the use of wavelengths may not be entirely abandoned after all, I
>don't know. Perhaps you or someone else here can shed some light on this
>controversy.
Appendix 1 of the metric bible states that the CPGM of 1975 redommended a
value for the speed of light. The second is the most accurately defined
unit that we have. It is axiomatic that
c = speed of light = lamda X frequency.
The frequency of a laser can be determined, and by the equation, so can its
wavelength. This gives a standard of length that is more accurate than the
previous metal bars. It could be stated that it as based on the wavelength
of a radiation of a specified frequency, or as the path travelled by light
in a specified time interval. The CPGM decided in favor of the latter form
of the statement.
Joseph B.Reid
17 Glebe Road West
Toronto M5P 1C8 TEL. 416-486-6071
