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 deflection of the magnetic needle? Explain.
Answers
Answer:
A convenient way of finding the direction of magnetic field associated with a current-carrying conductor is using right-hand thumb rule.
This rule is explained as follows:
Imagine that you are holding a current-carrying straight conductor in your right hand such that the thumb points towards the direction of current. Then your fingers will wrap around the conductor in the direction of the field lines of the magnetic field, as shown in Figure.
As per this rule , above the wire, magnetic field lines are emerging out of plane of figue. Hence magnetic field direction is from west to east.
Once we know the magnetic field direction surrounding the wire, we can determine the deflection direction of compass needle because we know that north pole of magnetic needle of compass will align in the direction of magnetic field