Hey guys. I am perhaps in the wrong section but the coursework help forum didn't seem right. My question is concerning the decrease in magnetism of an electromagnet. I have a ball hanging from an elctromagnet which will have the power source removed instantly. There may be some delay before the power to the electromagnet is cut but once this happens does the magnetism drop straight away to nothing. I understand it doesn't but does it drop off exponentially. The magnet has one of those soft iron cores so doesn't hold the magnetism very well after being turned off but what shape the curve is matters most. Magnetic Hysteresis? Also I noticed that when i turned the switch off the voltmeter didn't go to zero stright away but could but showed it drop down in more or less an exponential decrease - very quickly went from 8v to 4v, 1.5, 0.6v, 0. Do you think this means power is still getting to the electromagnet if the voltmeter is registering voltage like this. My intention was to show that residual magnetism has little effect once the ball is falling as the magnetism drops off and the ball is further away. Then I could put two curves next to each other and show a two fold decrese. it gets more complicated as the ball is accelerating. Then there is another factor which is that the ball is not accelerating linearly due to the pull from the electromagnet. This is probably a neglible effect and is not quantifiable with the information available. Really what i want to do is make my coursework seem a bit more in depth and add a bit of flashy maths. If I am only able to mention this effect it would still be worth it. Any help is much appreciated. Thanks very much.