Motors and Generators > 1. Motors and Magnetic Forces >

**Describe qualitatively and quantitatively the force between long parallel current-carrying conductors:**

- Wire with current gives magnetic field which exerts a force upon objects
- 2 parallel wires with a current produce magnetic fields that affect each other
- Same direction: fields attract and combine
- Opposite: Fields repel each other

- Use right hand grip (thumb – current, fingers – magnetic field) to determine direction and whether there will be attraction/repulsion
- Magnitude can be found with:
- In the above equation:
- F = force between conductors
- I
_{1}and I_{2}are the currents passing through the conductors - d is the distance between the conductors.
- l is the length of the conductors
- k is a constant (2x 10
^{-7})

- Force is increased with longer wires and less distance between them
- In one wire: