Current is passed from south to north through a conductor placed below a freely pivoted magnetic needle.

a) To which direction will the north pole of the magnetic needle turn?

b) Which is the rule used to arrive at this inference?

c) State the rule.

d) If the current flows in the conductor in the east west direction, what do you guess about the magnetic needle? Explain.

(a) If current is passed from south to north through a conductor placed below a freely pivoted magnetic needle, then the north pole of the magnetic needle will turn towards the east.

(b) Fleming’s Left-Hand Rule

(c) According to Fleming's left-hand rule, if the thumb, fore-finger and middle finger of the left hand are stretched to be perpendicular to each other as shown in the illustration at left, and if the fore finger represents the direction of magnetic field, the middle finger represents the direction of current, then the thumb represents the direction of force.

(d) By applying Right hand thumb rule we get that, when current is flowing in east- west direction then the magnetic needle will be deflected towards north direction.