Question

What is the force acting on an electric current flowing in an electric field, in a direction parallel to that of the field lines?

Answer 1

A current flowing parallel to a magnetic field will have no force exerted on it. The formula is `F=BIlsintheta` where `theta` is the angle between the field and the current, and `sin0=0`.

Explanation:

A force acts on electric charges when they move in a direction perpendicular to the direction of a magnetic field. If they are stationary in the field they experience no force, and if they move in the same direction as the field they experience no force.

For individual charges, the formula is:

`F=Bqvsintheta` where

`F` = force `(N)`
`B` = magnetic field strength `(T)`
`q` = charge `(C)`
`v` = velocity `(ms^-1)`
`theta` = angle between the velocity and the field

Current is simply a flow of charge, and the formula looks quite similar:

`F=BIlsintheta` where

`I` = current `(A)`
`l` = length of wire (or other current carrier) in the field `(m)`

In both cases, if the angle is `0^o`, `sin0=0` so the force is `0` `N`.