Question

A student fixes a white sheet of paper on a drawing board. He places a bar magnet in the centre and sprinkles some iron filings uniformly around the bar magnet. Then he taps gently and observes that iron filings arrange themselves in a certain pattern. 

1. Why do iron filings arrange themselves in a particular pattern?
2. Which physical quantity is indicated by the pattern of field lines around the bar magnet?
3. State any two properties of magnetic field lines.

Answer 1

1. When iron filings are placed in a magnetic field around a bar magnet, they behave like tiny magnets. The magnetic force experienced by these tiny magnets make them rotate and align themselves along the direction of field lines.
2. The physical property indicated by this arrangement is the magnetic field produced by the bar magnet. 
3. Magnetic field lines never intersect, magnetic field lines are closed curves.