Question

Describe the activity that shows that a current-carrying conductor experiences a force perpendicular to its length and the external magnetic field. How does Fleming’s left-hand rule help us to find the direction of the force acting on the current-carrying conductor?

Answer 1

• Take a small aluminium rod AB (of about 5 cm). 
• Using two connecting wires suspend it horizontally from a stand, as shown in Fig.
• Place a strong horse-shoe magnet in such a way that the rod lies between the two poles with the magnetic field directed upwards. 
• For this put the north pole of the magnet vertically below and south pole vertically above the aluminium rod.
• Connect the aluminium rod in series with a battery, a key and a rheostat.
• Now pass a current through the aluminium rod from end B to end A.
• It is observed that the rod is displaced towards the left. 
• You will notice that the rod gets displaced. 
• Reverse the direction of current flowing through the rod and observe the direction of its displacement. 
• It is now towards the right.