Question

How would you determine the magnitude of the magnetic force on a `120 m` length of line?

An electric power line carries a current of `1100 A` in a location where the earth's magnetic field is `6.0 ✕ 10^-5 T`. The line makes an angle of `75°` with respect to the field.

Answer 1

`vecF~~7.65N`

Explanation:

The magnitude of the magnetic force is given by `vecF=vec(B)vec(I)lsintheta`, where:

• `vecF` is the vector value for the magnetic force (`N`)
• `vec(B)` is the vector value for the magnetic field strength (`T`)
• `vecI` is the vector value for the current (`A`)
• `l` is the length of material being acted upon by the magnetic field (`m`)
• `theta` is the angle between the current and magnetic field (hence why the vector arrows are needed)

The arrows are there for the vector values, as `F`, `B`, and `I` are part of a vector diagram:

Using the equation, we get:
`vecF=(6*10^(-5))(1100)(120)sin75~~7.65N`