The SI ampere is defined by fixing the value of which quantity?
The force between two parallel current-carrying wires
The magnetic constant of vacuum
The elementary charge✓Respuesta correcta
The resistance of a standard resistor
Explicación
One ampere is the current corresponding to the flow of 1/(1.602 176 634 × 10⁻¹⁹) elementary charges per second. The older definition used the force between two current-carrying conductors and fixed the magnetic constant instead, which now has to be measured.