Wire with current flowing going perpendicular to a magnetic field will experience a force! $F=IlB\sin \theta$ Where $\theta$ is the angle made with the current and the field, if its perpendicular then its $90°$.
Magnetic field strength: Magnetic flux density, measured in Teslas! $(T)$
Tada right hand rule
Make sure all these things are 'orthogonal' to each other
Also use your right hand not your left hand!!!
'Bunched up field line idea'
Currents going in the same direction will attract each other, thinking of the right hand rule from the perspective of each wire.
Similarly, if the current is going in separate directions they will repel.
The classic application:
