# What is Magnetic coil: Definition and 13 Discussions

An electromagnetic coil is an electrical conductor such as a wire in the shape of a coil, spiral or helix. Electromagnetic coils are used in electrical engineering, in applications where electric currents interact with magnetic fields, in devices such as electric motors, generators, inductors, electromagnets, transformers, and sensor coils. Either an electric current is passed through the wire of the coil to generate a magnetic field, or conversely, an external time-varying magnetic field through the interior of the coil generates an EMF (voltage) in the conductor.
A current through any conductor creates a circular magnetic field around the conductor due to Ampere's law. The advantage of using the coil shape is that it increases the strength of the magnetic field produced by a given current. The magnetic fields generated by the separate turns of wire all pass through the center of the coil and add (superpose) to produce a strong field there. The more turns of wire, the stronger the field produced. Conversely, a changing external magnetic flux induces a voltage in a conductor such as a wire, due to Faraday's law of induction. The induced voltage can be increased by winding the wire into a coil because the field lines intersect the circuit multiple times.The direction of the magnetic field produced by a coil can be determined by the right hand grip rule. If the fingers of the right hand are wrapped around the magnetic core of a coil in the direction of conventional current through the wire, the thumb will point in the direction the magnetic field lines pass through the coil. The end of a magnetic core from which the field lines emerge is defined to be the North pole.
There are many different types of coils used in electric and electronic equipment.

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1. ### B Magnetic force driving a small iron ball

How can I calculate the force from magnetic field of a solenoid, grabbing a small iron ball? I want to use the good old simple F=ma formula in order to calculate the ball's acceleration. But can't find a formula to somehow convert the known field quality (in unit Tesla) to Force (in unit...
2. ### Making a replacement Magnetic coil for my ride-on lawnmower

So voltage is 12v the coil is 80 watts
3. P

### What is the Relationship Between Sound and Magnetic Frequencies?

Greetings! I was asked to provide an introduction: I am a retired Professor, in Music of all fields! I come from a family of engineers. I have long been researching sound and it's relationship with magnetic frequencies. I am also engaged in the development of a battery using permanent magnets.
4. ### Stopping a battery from shorting (while driving a magnetic coil)

Can anyone tell me how to determine the minimum resistance a battery needs to stop it from shorting? for example I'm making an electro magnet, with a 1.5v dc battery cell, but when i turn it on it just drains the battery.
5. ### I Force on Steel Bar Inside Solenoid

Hello all. Me and some friends are building a coil cannon, and we've been doing some calculations [I know its unecessary but... well, we're physicists! (well, physics students...)]. But we got stuck. How to calculate the force acting on a steel bar (or some other ferromagnetic material, maybe...
6. ### Magnetic Forces on objects in nonuniform fields

I have this question which I need to solve . But I am unable to. Suppose I have a current ring of radius R and current I (constant). at a distance x from the centre of the ring, I have a iron disk (radius r and thickness t) present in the plane of the ring. This disk will be attracted to the...
7. ### Induced current of a coil on another coil

Homework Statement We have two coils of copper wire, drawn below. One has a battery connected to it. The other one has a galvonometer connected. If the coil with the voltage is moved closer as shown in the picture, with considerable velocity, what direction will the current induced on the other...
8. ### Two coils of wire with the same size and shape

Homework Statement Two coils of wire that have same shape and dimensions are thickly rolled up so that the coincide, they only differ in number of coils (windings) N1 for the firs one and N2 for the second one (N1<N2). When there's constant current in the first one and there's no current in the...
9. ### Wanted: Looking for a helmholtz coil in Brisbane, QLD AUS

Hi guys, I'm a typical nerd that wanted to do an at home science project but don't want to spend lots of money on this coil. I would love to borrow/rent one if someone could help me. Otherwise if someone new a cheap supplier that i could get one off? It looks like either of these pictures :)...
10. ### Design 1.5 A Solenoid & Charge 1.5 V Battery

Hey All, I'm trying to design a solenoid that would generate about minimum 1.6 A of current in order for me to charge up a 1.5 A 1.5 V battery. I already designed one which is about 10CM in length and unknown number of turns (as I used a drill to wind the coils around it. so I would guess its...
11. ### Changing Potential Energy of a Magnetic Coil

Homework Statement A coil with magnetic moment 1.40 Am^2 is oriented initially with its magnetic moment antiparallel to a uniform magnetic field of magnitude 0.830 T. What is the change in potential energy of the coil when it is rotated 180 degrees, so that its magnetic moment is parallel...
12. ### Faradays law: magnetic coil question

Homework Statement (The information is for several questions and i have posted one of them) Two coils magnetically coupled, Voltage of 240v, 50Hz applied to coil 1, current of 2A flows, second coil connected only to a high impedance rms voltmeter reading 100v find: The peak total flux...
13. ### Why Does an Aluminum Ring Levitate Above a Magnetic Coil?

I don't know how to answer these questions. :( I know the alternating current makes the magnetic field changes. And the changing magnetic field generates emf.But I don't know why the emf is large enough to push the aluminum ring upward, and how come it goes up? thx a lot.