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主题:【原创】基本单位之间的关系 -- 橡树村

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家园 千克定义估计又要改了

Proposed future definition

Since a coulomb is approximately equal to 6.24150948×10^18 elementary charges, one ampere is approximately equivalent to 6.24150948×10^18 elementary charges, such as electrons, moving past a boundary in one second.

As with other SI base units, there have been proposals to redefine the kilogram in such a way as to define some presently measured physical constants to fixed values. One proposed definition of the kilogram is:

“ The kilogram is the mass which would be accelerated at precisely 2×10^-7 m/s^2 if subjected to the per metre force between two straight parallel conductors of infinite length, of negligible circular cross section, placed 1 metre apart in vacuum, through which flow a constant current of exactly 6 241 509 479 607 717 888 elementary charges per second. ”

This redefinition of the kilogram has the effect of fixing the elementary charge to be e = 1.60217653×10^-19 C and would result in a functionally equivalent definition for the coulomb as being the sum of exactly 6 241 509 479 607 717 888 elementary charges and the ampere as being the electrical current of exactly 6 241 509 479 607 717 888 elementary charges per second. This is consistent with the current 2002 CODATA value for the elementary charge which is 1.60217653×10^-19 ± 0.00000014×10^-19 C.

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