Search results
Results From The WOW.Com Content Network
Krypton-81 is useful in determining how old the water beneath the ground is. [10] Radioactive krypton-81 is the product of spallation reactions with cosmic rays striking gases present in the Earth atmosphere, along with the six stable or nearly stable krypton isotopes. [11] Krypton-81 has a half-life of about 229,000 years.
There is a precedent for changing the underlying principles behind the definition of the SI base units; the 11th CGPM (1960) defined the SI metre in terms of the wavelength of krypton-86 radiation, replacing the pre-SI metre bar, and the 13th CGPM (1967) replaced the original definition of the second, which was based on Earth's average rotation from 1750 to 1892, [18] with a definition based ...
This definition has since been changed (see krypton). At the same time, the International Prototype Meter was used as standard for the length of a meter until 1960, [54] when at the General Conference on Weights and Measures the meter was defined in terms of the orange-red emission line in the electromagnetic spectrum of the krypton-86 atom in ...
Main page; Contents; Current events; Random article; About Wikipedia; Contact us; Help; Learn to edit; Community portal; Recent changes; Upload file
Krypton is used in some photographic flashes for high speed photography. Krypton gas is also combined with mercury to make luminous signs that glow with a bright greenish-blue light. [39] Krypton is mixed with argon in energy efficient fluorescent lamps, reducing the power consumption, but also reducing the light output and raising the cost. [40]
Furthermore, nothing was said about why krypton-86 instead of Kr-78, Kr-80, Kr-82, Kr-83, or Kr-84, especially since krypton-84 is the most common isotope - 57 percent of the total atoms of krypton. Please explain. 98.67.96.19 ( talk ) 14:47, 11 August 2012 (UTC) [ reply ]
Spectral lines of krypton: Other properties; Natural occurrence: primordial: Crystal structure ... 86 Kr 17.3% stable
Shqip; Simple English ... the metre was redefined in terms of the wavelength of a spectral line of the krypton-86 atom (krypton-86 being a stable isotope of an inert ...