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.
- Take a drawing sheet and fix it on a smooth table with adhesive tape.
- Place a bar magnet in the middle of the drawing sheet and draw its boundary with a sharp pencil.
- 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.
- 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.
- Again mark the position of the other end (N-pole) of the compass needle.
- Repeat the steps 4 and 5, till you reach the other end (S-pole) of the bar magnet.
- Join all the points with a sharp pencil to get a smooth curve.
- Put the compass at some other points near the N-pole of the magnet and draw another magnetic field lines. Similarly, draw many field lines on both the sides of the bar magnet as shown in figure.
- 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.