Force on a current
A current carrying conductor at right angles to a magnetic field experiences a force at right angles to the current and the field.

Fleming's left hand rule can be used to find the direction of the force.

The size of the force is directly proportional to:

the size of the current            the strength of the field        the length of conductor in the field

How big is a Tesla? If we say a Telsa is the field strength that would produce a force on 1 N in a 1m long conductor carrying 1 A then

       so        1 Tesla = 1 N / A m