Electricity Magnetism and Metal Detector | How do they work?

Friends, you must have seen while visiting the shopping mall or any important place that the security guards there have a device in their hand. The device starts making beep sound if you have any metal such as coin or bike’s key. Yes, my friends, I am talking about metal detector. Using this technology, military and security guards around the world pay security service. Actually, the metal detector is the technology based on science and electromagnetism. Let’s know how they work.

Electricity and Magnetism:

Friends, today’s metal detector is not a new technology at all. Though it is used for security purpose now, it was invented to find out hidden treasures. However, now we will try to find how this technology works. Friends, Electricity and Magnetism are such two topics in physics that are strongly related to each other. You can say it, two souls in one body.

So, where there is electricity, there is magnetism. And electricity is made there where magnetism is present. Let’s think the matter deeply. Now think, the electricity you use at your home where does it come from? Maybe it is coming from a power station (hydroelectric, coal based, oil based, natural gas based, solar, wind wave, nuclear power etc.) or a generator at your home.

However, now the question is, how do these power stations create electricity? Suppose, in the hydroelectric power station, a barrage is built at the mouth of a river. The strong current of water is produced there. A large turbine is set at the mouth of the current. The turbine moves by the strong flow of water. An electric generator is planted with the turbine that produces electricity by using the moving power.

Similarly, a coal-based station works. Coal is fired in a large oven to boil a lot of water. The hot water emits the vapor that helps to move a turbine. And the turbine is fitted with a generator which produces electricity by using the moving power.

So, the generator is coming for each case. Now the question is, how does a generator produce electricity? In general, a generator is a big copper drum. That means a large copper coil is present in it. There is magnetic field around this copper coil. When this coil moves forcefully inside the magnetic field, electricity is produced like a magic.

We operate electric appliances such as washing machine, electric fan or electric motor by utilizing electricity. These electric appliances work in the opposite way of an electric generator. When electricity flows through the electric motor, a variable magnetic field is created inside the copper coil of the motor. A permanent magnetic field always pulls it backwards. As a result, the motor starts moving.

However, from the above discussion, we are clear now that we can create magnetism by using electricity and electricity by using magnetism. This theory was first given by a Scottish scientist – Maxwell.

How does Metal Detector work?

Different metal detectors work differently. But each of them has a common science. A cable coil is present inside the metal detector which is called transmitter coil. When electricity flows through this coil, a magnetic filed is created around it.

Now, if you pass the metal detector over a metal object, some changes are brought about in the atom of the metal object. That means, the magnetic field coming from the metal detector changes the orbit of electrons of the metal object. From Maxwell’s theory, we know that if any magnetic field changes the atom of any metal object, electricity is generated there.

So, in one word, the metal detector enter a little electricity in the metal object. Again, Maxwell’s theory says that if any electricity passes over a piece of metal, magnetism is created there. So, when a metal detector is passed over a metal object, the magnetism of metal detector enter electricity inside the metal object. As a result of entered electricity, another magnetism is created there which is called second magnetism.

Now, the metal detector detects the second magnetism. There is a second cable coil inside the metal detector which is called receiver coil. It is connected to a circuit which contains a Loudspeaker. I have mentioned earlier that another magnetism is created in the metal object which is detected by the coil of the detector and electricity is generated there. Now this electricity goes to the Loudspeaker and makes beep sounds. And thus a metal detector detects a metal object using magnetism and electricity.

Hopefully, you have learned many important things from today’s post. Though the post was not very long, you have got the main ideas. If you like the post, don’t forget to share it. Comment on the post and give your opinion. Thank you.