MAGNETIC EFFECT OF CURRENT
MAGNETIC FIELD AND MAGNETIC LINES OF FORCE
Magnetic field may be defined as the space around a magnet in which the affect of magnet can be experienced. The magnetic field of a magnet is represented by equidistant parallel lines called magnetic lines of force. The magnetic line of force may be defined as the path along which the north pole of compass needle moves.
To see how the magnetic lines of force look like, take a bar magnet and a magnetic compass needle. A magnetic compass needle consists of a magnetic arrow whose tip represents the north pole and tail represents the south pole. To obtain magnetic lines of force, place the bar magnet on a plane sheet of paper. Bring the compass needle near the north pole of the magnet. When the compass is brought near the north pole of the magnet you will observe that the compass needle deflects itself in such a manner that its south pole directs towards north pole of bar magnet and the north pole of the compass needle directs away from the north pole of the bar magnet. Now, mark the positions of tip and tail of compass needle with the help of a sharp pencil. Move the compass needle so that it’s south pole touches the point previously occupied by its north pole. Once again mark the new positions indicated by poles of needle. Keep on repeating this process until you reach the south pole of the bar magnet. Now, join all the points marked on the paper to obtain a smooth curve. This curve represents one magnetic line of force. In the similar manner, you can draw as many magnetic lines of force as you like.
Diagram of magnetic line of force by using compass needle
Properties of Magnetic Lines of Force
Following are the important properties of magnetic lines of force:
- The magnetic lines of force originate from north pole of a magnet and ends at its south pole.
- No two magnetic lines of force can intersect each other because if the two magnetic lines of force intersect each other, it would mean that the needle would point towards two directions at the point of intersection, which is not possible.
- The degree of closeness of magnetic lines of force shows the relative strength of magnetic field.
Test Your Understanding and Answer These Questions:
- What do you meant by magnetic field?
- What are magnetic lines of force? Mention important properties of magnetic lines of force. How is the direction of a magnetic line of force determined at a point?
- How will you draw the magnetic lines of force of a bar magnet?
- Draw a diagram to show the magnetic lines of force due to a bar magnet.
- Why two magnetic lines of force do not intersect each other?