Question

How is the magnetic field strength of the points denoted in the given figures decided? Is it the same at all the given points in both the cases?

Answer 1

The magnetic field strength at a point around a magnet is decided by:

• How tightly packed or loosely spaced are the field lines at the point
• The location of the point with respect to the magnet.

Closely packed magnetic field lines indicate that the field strength at the point is high. Points closer to the magnetic poles also experience a strong magnetic force.

Case 1: the field is said to be uniform because the magnetic field lines are straight from the north pole to the south pole, and are parallel to each other. In such a case, the field strength would be the same at all points between the two given poles as all points have the same amount of field lines going through them. Therefore, points $1,2,$ and $3$ have the same field strength.

Case 2: the field is not uniform because the magnetic field lines are curved from the north pole to the south pole, and are not parallel to each other at all points.

• Point $4$ has the most magnetic field strength as it is located the closest to a magnetic pole out of the given three points.
• Point $6$ has the second most magnetic field strength as it is located the closer to the magnet but not as close as point $4$ and not as far as point $5$.
• Point $5$ has the least magnetic field strength as it is the farthest from the magnet and the field lines are not as closely spaced as they are at the other two points.