Question

Two long, straight wires are parallel and 10cm apart. One carries a current of 2.0A, the other a current of 5.0A.(a) If the two currents flow in opposite directions, what is the magnitude and direction of the force per unit length of one wire on the other?(b) What is the magnitude and direction of the force per unit length if the currents flow in the same direction?

Answer 1

To solve this problem we need to consider the concept about Ampere's Law.

The Ampere's law say that,

`F = (\mu_0 I_1I_2)/(2\pi R)`

Where,

F= Mangetic field

`\mu_0 =`Permeability of free space
`(4\pi*10^(-7)})`

I =current

R= Radius from the wire in meters.

A) At the first case the force on wire is repulsive, replacing our values

`F = \frac{4\pi*10^(-7)}*2*5}{2\pi *10*10^(-2)}`

`F= 2*10^(-5)N \rightarrow` In repulsive direction.

B) At the second case de Force flow in the same direction, then we have,

`F = \frac{4\pi*10^(-7)}*2*5}{2\pi *10*10^(-2)}`

`F= 2*10^(-5)N \rightarrow` In attractive direction