Question

The unit of current, the ampere, is defined in terms of the force between currents. Two 1.0-meter-long sections of very long wires a distance 2.5 m apart each carry a current of 1.0 A. You may want to review (Pages 784 - 787) . What is the force between them?

Answer 1

Answer:

1.6 x $10^{-7}$ N

Explanation:

If the force between two actual wires has this value, the current is defined to be exactly 1 A.

The force between two parallel wires carrying current can be defined as,

F=  μ$I_{1}$ $I_{2}$ L/ 2πd

where,

current $I_{1}$ = 1Amp

current $I_{2}$ = 2amp

Length 'L'= 1m

distance 'd'= 2.5m

permeability of free space 'μ'= 4πx$10^{-7}$ N/m

Putting the above values in the equation,

F=( 4πx$10^{-7}$ x 1 x 2 x 1 )/ 2πx2.5

F= 1.6 x $10^{-7}$ N