Physics Form 5: Chapter 3 - Forces on a Current-carrying Wire

The direction of the magnetic force, F acting on the wire can be determined by using Fleming’s left hand rule.





Explanation:

• The straight lines with arrows show the direction of the magnetic field between the north and south poles.
• The circular lines with arrows show the direction of the magnetic field of the current.
• When the two fields are in the same direction and they produce a stronger combined magnetic field. 
• When the two fields act in opposite directions and they produce a weaker magnetic field.
• Interaction between the magnetic fields produce a catapult field. Thus, the wire carrying current experiences a resultant force in the direction from the stronger to the weaker magnetic field