Briefly explain an activity to plot the magnetic field lines around a bar magnet. Sketch the field pattern for the same specifying field directions.
A region A has magnetic field lines relatively closer than another region B. Which region has stronger magnetic field. Give reason to support your answer.

Explanation

1. Take a drawing sheet and fix it on a smooth table with adhesive tape.
2. Place a bar magnet in the middle of the drawing sheet and draw its boundary with a sharp pencil.
3. Place a magnetic compass near one end of the magnet (N-pole) and mark the positions of the two ends (N and S-poles) of the compass needle using a sharp pencil.
4. Shift the compass from this position and place it in such a way that S-pole of its needle is on the point you marked in previous step for N-pole.
5. Again mark the position of the other end (N-pole) of the compass needle.

6. Repeat the steps 4 and 5, till you reach the other end (S-pole) of the bar magnet.
7. Join all the points with a sharp pencil to get a smooth curve.
8. Put the compass at some other points near the N-pole of the magnet and draw another amgnetic field lines. Similarly, draw many field lines on both the sides of the bar magnet as shown in figure.
9. Observe the pattern of the magnetic field lines.
Result: Magnetic field lines can be drawn around a bar magnet using a magnetic compass. The field lines do not cross each other.
Region A has stronger magnetic field. This is due to the strength of the field is proportional to the relative closeness of field lines.