Question

Two long straight wires are parallel to each other and are separated by 78 mm. The current in wire 1 is 3.55 A and the current in wire 2 is 2.75 A. What is the force per unit length between the two wires?

Answer 1

`2.5\cdot 10^(-5)N`

Step-by-step explanation:

The force per unit length between two current-carrying wires is given by:

`(F)/(L)=(\mu_0 I_1 I_2)/(2\pi r)`

where

`\mu_0` is the vacuum permeability

`I_1, I_2` are the two currents

r is the separation between the wires

In this problem, we have

`I_1 =3.55 A` is the current in the first wire

`I_2 = 2.75 A` is the current in the second wire

`r=78 mm=0.078 m` is the separation between the wires

Substituting into the equation, we find

`(F)/(L)=((4\pi \cdot 10^(-7) H/m)(3.55 A)(2.75 A))/(2\pi (0.078 m))=2.5\cdot 10^(-5)N`