# Electricity and Magnetism

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## What is Electricity?

Electricity is the motion of electric power/charge. Electricity can be obtained from renewable and non-renewable sources of energy.

Wind and water are the natural/renewable sources that help generate power by rotating turbines.

Electricity can also be obtained from various non-renewable sources viz: coal, natural gas, nuclear power, etc. These resources are considered primary/fundamental sources of energy.

‘Electromagnetism’ is a combination of electricity and magnetism, and they both are inter-related, these relations are described by Maxwell’s Equations.

In this article, we will discuss what is magnetism, what causes magnetism, and the relation of electricity with magnetism.

### What is Magnetism?

Do you know what a magnet is? A magnet is a material that generates an invisible field around it called the magnetic field; this field is responsible for generating a force (magnetism) that pulls an object like iron filling towards itself; also repels the objects.

Magnetism is the property of a magnet to attract or repel objects. Like electricity, magnetism is also caused by the motion of electric charge.

Not all magnets possess the same property, they are categorized into three following forms:

• ### Permanent Magnets

These magnets are called persistent magnets because they persist in their magnetism after the removal of the magnetic field around them. Some of the examples of permanent magnets are:

1. Neodymium Iron Boron (NdFeB)

2. Samarium Cobalt (SmCo)

3. Ceramic or ferrite magnets

4. Alnico

• ### Temporary Magnets

These magnets are non-persistent in their magnetism retrieving attribute. These magnets have the quality to behave like their boss ‘permanent magnets’; however, they lose magnetism after the removal of the magnetic field around them. One of the examples of such type is a soft iron device like a paper clip.

Electromagnets are also referred to as temporary magnets because they possess magnetism through electricity. As soon as the power of the battery ceases, these magnets lose their magnetic property.  So, what is an electromagnet?

• ### Electromagnet

An electromagnet is made by winding the multiple loops of a wire around a current-carrying conductor. An example of this is the Solenoid.

To magnetize an electromagnet, a current is passed through the solenoid and a magnetic field generates around it. The strength of the magnetic field inside the coil is high. The magnetic field’s strength depends on the magnitude of the current and the number of turns of wire.

Let’s suppose that wire is wound around a non-magnetic material like a wooden stick, we observe that the magnetic field is not high. However, if we replace it with a ferromagnetic material like iron,  the strength of magnetic field wire rises dramatically.

Overall, the strength of the magnetic field relies mainly on the magnetic material being used. Certain magnetic materials that possess varying magnetism, let’s discuss these:

Electromagnetism is a phenomenon in which electricity and magnetism are related to each other. Their relationship can be described with the help of Maxwell’s equations.

### What is Magnetic Material?

The materials attract or repel the objects brought in their vicinity, according to their ability to generate the magnetic field. The response of these materials is ascertained by the magnetic dipole moment associated with their intrinsic angular momentum, or spin, of their electrons. There are three types of magnetic materials. These are:

• Ferromagnetic

• Diamagnetic

• Paramagnetic

1. ### Ferromagnetic Materials

These materials have some unpaired electrons in their atoms, and they generate a weak magnetic field around them because atoms (magnetic domains) inside the magnetic materials are aligned in a way that they cancel out each other, as you can see in the image above.

An external magnetic field is applied to the material to align the atoms in a way that generates the magnetic field. However, after the removal of the electric field, this material persists with its magnetism, i.e., remanence. Such examples are cobalt, diamagnetic nickel, and iron.

1. ### Diamagnetic Material

The materials that don’t generate the magnetic field are called diamagnet because atoms in these materials have paired electrons, that’s why they don’t generate their own magnetic field.

On applying an external magnetic field to these materials, the strength of the magnetic field is so weak that it is unnoticeable. It’s because they don’t have unpaired electrons and are very less influenced by an external field.

Point to Remember:

Most of the elements in a periodic table are diamagnetic.

1. ### Paramagnetic Material

Paramagnetic materials are less susceptible to the magnetic field. Unlike ferromagnetic materials, paramagnetic materials don’t reveal the property of remanence because they lose the property of magnetism after an external magnetic field is removed around them.

These materials bear attractive forces that are 10,000 times weaker than ferromagnetic materials, that’s why they are considered non-magnetic.

### What is Magnetic Induction?

Magnetic or electromagnetic induction is the phenomenon of generating an electromotive force or EMF around the current-current conductor in a changing magnetic field. So, EMF is given by:

E = - N$\frac{d\varphi }{dt}$

Here,

N = no of turns of wire around the conductor

$\frac{d\varphi }{dt}$ = flux changing with time dt

1. What is magnetic induction and how does it work?

Electromagnetic induction occurs whenever a magnetic field and a current-carrying conductor move relative to one another, so the conductor crosses the magnetic lines of force in the magnetic field.

The current produced because of electromagnetic induction is high when the magnet (coil) is strong, it moves faster, and the coil has more turns.

2. How is an electromagnet made?

We can make an electromagnet by taking a ferromagnetic material like an iron nail. Winding a wire around this nail and connecting it to the battery or a power source. Now, as the current passes through the winding, this arrangement behaves like a magnet.

However, these arrangements don’t possess magnetic remanence; that’s why they are called temporary magnets. We can use both AC and DC sources to produce electromagnets.

3. Can you have magnetism without electricity?

No, we can’t have magnetism without electricity. Let’s suppose that a rod has a wire winded around it and it is standing still; it will not generate magnetism. However, when the battery supplies electricity to it, this arrangement behaves like a magnet.

4. Can a magnet power a light bulb?

No! It’s because the current generated by a magnet over a single wire doesn’t generate enough power to light a bulb; that’s why lighting a bulb requires an alternate way to generate more power in a certain time.