Thread: Electromagnet Question

I have this hypothesis and I'm wondering if it's right or not.

"If the diameter of a nail is small then the electromagnet strength is stronger than that of a bigger nail if the amount of coil is the same for both nail."

I try testing the experiment and it didn't go so well... So I kinda need to know if my hypothesis is wrong or right.

I really appreciated if someone can anwser this and...quick Thank You

No, the larger nail may take longer to magnetise, but I'm fairly confident if it is the same material it's maximum field strength density will be the same in both cases, thus the larger nail should have more 'pulling power'.

Try a cone shaped piece of metal you'll find each end can 'lift' the same weight but the larger end will simply have a less dense field per unit area.

Thank You

Is it also true that larger the diameter of the coil increases the strength of the electromagnet as well

oooh...

There's a lot of maths and equations involved to strictly answer that question, it is the power applied to the coil that determines field strength and size, the more power into the smaller area the denser will be the field, so a larger coil with the same power will produce a weaker yet larger field.

Originally Posted by Megabrain

No, the larger nail may take longer to magnetise, but I'm fairly confident if it is the same material it's maximum field strength density will be the same in both cases, thus the larger nail should have more 'pulling power'.

So the bigger size nail will have more field stength but why? Electrons will flow from the negative side of the battery to the positive side as fast as they can when a wire is attached to them. How come the big nail have more "pulling power?"

What ever material you choose to magnetise, there is a limit to the amount of magnetism you can 'put in it' before it saturates. This is down to the material, e.g iridium magnets can be far stronger than iron ones, it's a function of the material. So, like filling bottles the bigger the bottle the more liquid it will hold.

I am talking here about magnetising the iron of course and then referring to it's magnetic properties after it has been removed from the energising coil.

How about gold and silver? Can they be magnetizd since they are not iron?

Not in a permanent sense. Aluminium and copper can exhibit magnetic fileds in certain cicumstances, so other metals may fall into this group.
(look up 'eddy currents').