Page 472 | Volume 2 | Chapter 27 | Testing and Testing Apparatus
Ques. What is the value of the International ampere as measured with the silver voltameter?
Ans. The International ampere is represented sufficiently well for practical use by the unvarying current which, when passed through a silver voltameter (as described above) deposits silver at the rate of .001118 gramme per second.
Ohm's Law and the Ohm.—The various tests here described depend for their truth upon the definite relation existing between the electric current, its pressure, and the resistance which the circuit offers to its flow. This relation was fully investigated by Ohm in 1827. Using the same conductor, he proved not only that the current varies with the pressure, but that it varies in direct proportion.
Ohm's law has already been discussed in a previous chapter and the several ways of expressing it are repeated here for convenience:
1. Amperes = volts / ohms;
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