1. Chai

    Induction , Permanent Magnet, Coil

    Hi, I could need some help here..... I have a question to this simulation. Faraday's Law 2.05 So, there happens induction , when a magnet is moved through coil. But I dont understand, why, when the magnet moves through and out of the coil, the sign of the voltage is different & when we change...
  2. F

    induced emf in a solenoid due to a rotating magnet

    Hey, I have come up with an idea for my EEI to measure the emf induced in a solenoid by a rotating magnet when the solenoid is not directly above the magnet (such that the magnetic field is not uniform). Previously I had to perform an experiment where the solenoid was on axis (see picture) and...
  3. S

    Spin and Magnet

    Suppose in a magnetic field which is in the z-direction we send a magnet with its N-pole directed in the x-direction. We know the magnet would rotate and become in line with the magnetic field. However, if we send a pure spin state |S_x,+> it can depart in the two opposite directions +z and -z...
  4. G

    Dipole magnet as a cathode

    Hey physics professionals. This is a somewhat odd request for info but I thought I'd run it up the flagpole here, see who salutes; I'm aware a dipole magnet can't be a cathode, what I can't find is any specific information as to why. The kicker is I'm going to attempt to explain this to an...
  5. W

    Holding down steel plate w/ multiple magnets: Does orientation matter?

    The picture below shows an image of a bed from a 3d printer, which I intend to equip with an array of 15 x 3 mm Neodym magnets to hold down a steel plate. The steel plate itself is not and can not be equipped with magnets. Theres a heated aluminium bed between magnets and steel plate and the...
  6. Y

    Neodymium magnet and electromagnet experiment

    Hi, I wanted to repel away a standard neodymium magnet by using an electromagnet. I got a nail, some coil, a neo magnet and a 9v battery. I wrapped some coil on the nail, and attached it to the battery. The problem is that the neo magnet attaches to the nail regardless if the nail is...
  7. O

    Is it possible to stop a bullet by just using a magnet?

    Stop it or deflect it? and what are the laws and the effects that I need to know to determine something like this?
  8. T

    spherical unipolar magnet

    imagine a spherical shell of magnets. they form a perfect sphere . they are all magnetized so the north pole is pointing out. what do the flux paths look like? this a real physical possibility and easy to make but i am curious as to your thoughts. thank you.
  9. M

    Magnetic moment of bar magnet, estimate

    The treatment for the magnetic moment of a bar magnet has been exhibited in most general physics and EM texts. How can the magnetic moment of a bar magnet be reasonably estimated from the total magnetic flux passing through the magnetized material in the plane that is perpendicular to the...
  10. G

    Electromagnetic induction and magnet shapes. Help !

    Hello. Can someone explain to me how different magnets have a different effect on electromagnetic induction? When you use a normal flat straight magnet the side(polarity) you put it in through a coil, makes the arrow of the Galvanometer move left or right. But if you use a horseshoe magnet it...
  11. X

    work done by a permanent magnet

    I recall that the energy stored in a magnetic field is half the volume integral of the dot product of magnetic field and flux density vectors (H and B). When you place a piece of iron near a magnet, it does a work by attracting it. If H is 0 (I think there is only the magnetic moment vector M...
  12. V

    Recommendation for strongest magnet?

    I'm looking to buy a a magnet which can detect drywall screws in the wall studs and ceilings joists. The screws will be covered over by drywall joint compound and drywall tape. Could someone suggest a very strong magnet which could easily pickup the screws which are covered over by tape and...
  13. kelsiu

    Why diamagnetic material is not repelled?

    When an external magnetic field is applied to a diamagnetic materials, their atomic current loops will tend to align in such a way as to oppose the applied field. Diamagnetism is the residual magnetic behavior when materials are neither paramagnetic nor ferromagnetic and most materials are...
  14. H

    Electromagnet to attract small iron pieces

    i want to build an electromagnet which can attract small iron pieces(2-3 mm long) at a distance of 10 cm from the magnet.I am using 24 awg. magnet wire.Please help .answer these questions - 1) How long magnet wire (24 awg) do i need? 2)How much current 3) what shud be least radius of solenoid...
  15. O

    Which side is the north pole of a magnet?

    If I want my glass exposing to the north pole of a magnet, does anyone have any suggestions on which side the north pole of a magnet is? Thanks in advance for any suggestions
  16. P


    why the broken bar magnet cannot attract each other?
  17. P

    Genius magnet ID and a prayer

    It is my prayer to apply my logic into God. When I make the new formula, I do not need to make something and only write down on the paper. By the radar, it is proved by the magnet as my ID. By ID, the world is predestination as already as history of God's vision and I do not know and just follow...
  18. W

    HELP! Wind turbine!

    Do you think this wind turbine generates any voltage at all?? As you can see in this video, there are magnets on the base board and a coil of wire sitting on top of the spoons that catch the wind. Do you think this would work for generating any voltage? All comments and suggestions welcome...
  19. R

    magnet deflecting charged particles, logical, but fictional problem.

    An alien civilization has crossed the galaxy to invade the Earth and enslave humanity, again. Their attacks have been successful so far because their assault troops are equipped with handheld weapons that project beams of charged particles (protons & electrons) at very high speeds, able to...
  20. T

    anything stronger than a magnet?

    Hi, is there anything stronger than a magnet at repelling itself? Or is there anyway to have a really strong electromagnet. I'm trying to develop something that repels itself but its force is too weak for use. I'm looking for some way to either boost this repelling force or looking for some...