How can iron filings be used to map the magnetic field of a bar magnet?

They path of travel can be recorded, this recording would show that the iron fillings are grouping towards the North Pole of the magnet and the South Pole. (Look to the picture) The iron fillings would show the magnetic field similar to this. Hope that helped! :)

Answer: 1.4 seconds which is the third optionexplanation: current is defined as the flow of charge per timetherefore, the equation that relates current, charge and time can be expressed as follows: i = δq / δtwhere: i is the current given = 1.8 ampereδq is the charge given = 2.5 coulombδt is the time required for the flow of the given charges to give the 1.8 ampere.substitute with the givens in the above equation to get the time as follows: 1.8 = 2.5 / δtδt = 2.5 / 1.8 = 1.38888 which is approximately 1.4 secondshope this was !