Defining Ampere and Coulomb

•The force between
parallel conductors can be used to
define the Ampere (A)

•If two long, parallel wires 1 m apart carry the same current, and the magnitude of the magnetic force per unit length is 2 x 10-7 N/m, then the
current is defined to be 1
A

•The SI unit of charge,
the Coulomb (C), can be defined
in terms of the Ampere

•If a conductor carries a steady current of 1 A, then the
quantity of charge that
flows through any cross section in
1 second is 1 C