Question

The iron fillings are concentrated at region of the bar magnet. *

both north pole and south pole
only north pole
only south pole
middle part of the bar magnet​

Answer 1

Answer:

When the iron filings are sprinkled, those very close to the magnet, where the magnetic force is the strongest, will cling to the magnet. Those filings a little farther away, where the magnetic force is less strong, will align themselves with the magnetic flux lines, but they will not be drawn to cling to the magnet.

Answer 2

Answer:

At both poles are the field lines most concentrated around a bar magnet

Iron filings make a pattern tracing field lines because each bit of iron is itself a tiny dipole. The force the dipole experiences is proportional to the strength of the dipole and the rate at which the magnetic field changes. The dipole tries to align itself with a magnetic field, but at the ends of a bar magnet, the field lines are very close together. What this indicates is that the magnetic field varies strongly over a short distance compared to the variation closer to the middle of the magnet.