Why is a current loop considered as magnetic dipole ?
Answers
Let us consider a plane loop of wire carrying current. At the upper face of loop, the current is anticlockwise, therefore it will behave as north pole. At the lower face of the loop, the current being flowing loop thus behaves as a sy magnetic dipole clockwise, it will behave as magnetic south pole. The current carrying stem of two equal and opposite magnetic poles and hence is a magnetic dipole.
ANSWER;___✍️
We know that electric current produces magnetic field according to Biot Savart’s law. We can use this law to find magnetic field of different current configurations.
If we calculate the magnetic field at any point on the axis of a current carrying ring , the field at large distance z is given by
B(z)=uoIA/2 piz^3………………….(1). Here,
z is distance on the axis of the ring from center of the ring. z>>>a, where a is radius of the ring.
uo is magnetic permeability of space.
A is area enclosed by the ring.
I is current.
On the other hand we can calculate magnetic field at large distance
on the axis of a bar magnet. It is found to be
B(z)=uoM/2 pi z^3…………………..(2). Here,
M is magnetic dipole moment of the bar magnet.
z is distance from center of the bar magnet on the axis of the bar magnet.z>>>>2l, where 2l is magnetic length of the bar magnet.
Comparison of eq.(1) and (2) clearly suggests that the current carrying ring acts as a magnet of magnetic moment IA.
To determine as to which side of the ring behaves as which magnetic pole we use the following practice method.
If we look at the ring perpendicularly ( perpendicular to it’s plane and if we find that the current flows in aNticlock wise direction the side of the ring on our side is North Pole and opposite side is South Pole. In the above observation if current is found to flow in clock wise direction then the side on our side is South Pole and opposite side is North Pole. See the figure.
