How Are Magnets Used in Technology, Medicine, and Industry?
Uses of magnets in daily life can be found in numerous electronic devices, including television, radio, microwaves, hard disks, motors, generators, and many more.
Magnets are divided into two types: permanent and temporary. The uses of magnets in everyday life vary depending on their type.
What are Permanent Magnets?
Materials that generate a magnetic field within their internal structure and do not rely on electricity to retain their magnetism are permanent magnets.
What are Temporary Magnets?
Many materials have the ability to inherit magnetic properties temporarily when in proximity with other magnetic materials, but these fade quickly, returning the material to its original nonmagnetic state. A magnet that loses its magnetic attribute once the permanent magnetic field or electronic current is removed, is a temporary magnet.
Let’s understand what the practical uses of a magnet in our everyday lives are.
What are the Properties of a Magnet?
Every magnet, irrespective of its size or shape, has two different poles - the north pole and the south pole. The magnetic property of these two poles is more than the rest of the magnet’s body, which means that the magnetic property is maximum in these areas.
Here are three main properties of magnets:
Attractive Property: Magnet attracts ferromagnetic materials like iron, nickel, cobalt, among others. Additionally, magnetic poles with opposing magnetic fields attract one another.
Repulsive Properties: Property of repulsion and attraction exists between two magnets. Like magnetic poles repel each other.
Directive Property: A magnet, suspended freely, will always point in a north-south direction.
What is the Use of Magnets?
The two types of uses of magnets in daily life are:
Electromagnets
Permanent magnets
Uses of Electromagnets
Electromagnets are temporary in nature as they only work under the influence of applied electric current. It is made from a coil of wire which behaves as a magnet when an electric current passes through it. An electromagnet is often wrapped around a core magnetic material like steel to enhance the magnetic field produced by the coil.
The strength of the magnetic field of these magnets can be altered by varying the power of the electric current. One can also change its polarity by altering the direction of the electric current.
For example, the method of magnetic separation is used to separate magnetic substances like steel and iron from waste material. The crane's long arm is fitted with an electromagnet. When the electromagnet is switched on and the arm is lowered over the heap of waste, the old iron and steel objects present in the waste get attracted to the electromagnet and stick to it.
Electromagnets are Also Used in the Following:
Generators
Motors
Transformers
Electric buzzers and bells
Headphones
Loudspeakers
Relays and valves
Data storage devices: VCRs, tape recorders, hard discs
Induction cooker
Magnetic locks
MRI machines
Particle accelerators
Mass spectrometers
We also find the use of electromagnet in other processes like joining two bogies of a train, in a crane (JCB) used to transport heavy materials and waste, and in-service centers and garages to lift heavy vehicles, etc.
The theory of electromagnetism applies to the following domains:
Electrostatics
Magnetic fields of slow and steady currents
Motional e.m.f. and EMI
Maxwell's equations
The propagation and radiation of EMW
Electric and magnetic properties of matter
Laws of conservation
Uses of Permanent Magnets
Permanent magnets are made of materials that inherit the magnetic field, and so the strength of the magnetic field cannot be altered.
These magnets cannot be demagnetized, unlike electromagnets.
So its uses can be found in devices like electric motors, magnetic recording and storage media, decorations, among others, where these properties are required.
For example, a small coil of wire and a permanent magnet inside a speaker transforms the electronic signal to sound vibrations.
A magnetic compass uses the directive property of the magnet. A compass has a magnetic needle that is pivoted from the center and suspended freely so it can rotate. The needle of the compass when suspended freely will always point in the north-south direction. This compass is used by soldiers, sailors, hikers, etc.
Magnets are also used to hold objects like box lids, magnetic stickers, the doors of the refrigerator or cupboards, etc.
Permanent Magnets are Used in the Following:
Speakers
Headphones/earphones
Mobile phones
Cars
Generators
Television
Transducers
Hard drives
Sensors
Practical Uses of Magnets
A. Electromagnets
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1. Home Appliances
Most of the electric appliances that we use in our homes work on the basic principle of electromagnetism. Some uses of electromagnets in a home include the following:
1. Electric fan
2. Electric doorbell
3. Induction cooker
4. Magnetic locks
So, how is a magnet used in an electric fan and doorbells?
In an electric fan, the EMI keeps the motor rotating, which in turn makes the blades of a fan rotate.
However, in an electric doorbell, when we press the button, the electromagnetic force of the coil gets energized and the bell makes a sound.
2. Medical Equipment
An MRI or magnetic resonance imaging lets your doctor see the organs, bones, and tissues inside your body without having to do surgery. MRI works on the principle of electromagnetism, employing powerful magnets that produce a strong magnetic field.
3. Memory Storage Devices
The data or information in electronic gadgets and phones are stored in the electromagnetic format in the form of bytes and bits.
4. Computer Hardware
Computer hardware also has a magnetic tape that works on the electromagnetism principle.
5. Communication Devices and Power Circuits
Without electromagnets, the mobile phones we use to communicate with people around the world could not have taken place. The electromagnetic pulses and the interaction of the communication signals make mobile phones and telephones very handy.
6. Others
In devices like electric fans, electric bell, telegraph, debit cards, credit cards, etc.
Did You Know?
In the olden days, electromagnets were mostly used in the data storage of VCP and VCR.
B. Permanent Magnets
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There are endless uses of permanent magnets. Some practical uses of the magnet are:
Door magnets: Magnets are used to hold objects so they don’t shut on their own, like refrigerators, boxes, and containers, cupboards, etc.
Magnetic name tags
Magnetic jewelry
Magnetic clasps
Magnetic water treatment: A method of passing hard water through a magnetic field to reduce its effects. It is a non-chemical alternative.
Magnetic filter
Adhesive magnets
Magnetic pickup tools
Magnetic knife holder
Magnetic tray
Compass
Magnetic toy
Maglev train
Induction cooker
Telephone
Cell phone
Clocks
Scientific instruments
The other three uses of permanent magnets are:
1. Refrigerators
One of the most important uses of permanent magnets is found in closing the door of a refrigerator. The gasket of the refrigerator that seals the door closed, has a thin inner magnetic strip, which is a permanent magnet.
2. Automobiles
Hybrid and electric vehicles use powerful permanent magnets. Magnets used in these automobiles are made of materials with a high proportion of rare earth permanent magnets, which are both expensive and in limited supply.
3. Jewelry
Jewelry like bracelets, earrings, necklaces, and beads are made of permanent magnets because these magnets help in keeping jewelry clasped closed.
Do You Know?
Permanent magnets are also used in tools like screwdrivers? Screw drivers attract the screws. They are handy when dealing with small screws or hard-to-reach places.
FAQs on Uses of Magnets: Everyday Applications & Scientific Importance
1. What are the two main types of magnets and their fundamental differences?
The two main types of magnets are permanent magnets and electromagnets. The key difference lies in how they generate magnetism. Permanent magnets, made from materials like iron or nickel, have a persistent magnetic field without needing an external power source. Electromagnets are temporary; they are created by passing an electric current through a coil of wire, often wrapped around a core. Their magnetic field only exists when the current is on and its strength can be controlled.
2. What are some common examples of magnets used in everyday life?
Magnets are essential in many everyday items. Some common examples include:
- In Home Appliances: Refrigerator door seals, microwave ovens, electric fans, and doorbells.
- In Electronics: Speakers, headphones, computer hard drives, and mobile phones.
- For Holding and Fastening: Magnetic knife holders, cupboard latches, and magnetic stickers.
- In Navigation and Tools: Magnetic compasses used for direction and screwdrivers with magnetic tips to hold screws.
3. How is the principle of electromagnetism applied in a device like an electric bell?
An electric bell uses an electromagnet to create its ringing sound. When you press the switch, an electric circuit is completed, and current flows through a coil, turning it into an electromagnet. This magnet attracts a soft iron arm (hammer), which strikes a gong. The movement of the arm also breaks the circuit, deactivating the electromagnet. A spring then pulls the arm back to its original position, completing the circuit again. This rapid make-and-break cycle causes the continuous ringing.
4. What is the importance of magnets in modern medicine?
The most significant use of magnets in medicine is in Magnetic Resonance Imaging (MRI) machines. These devices use powerful superconducting magnets to generate a strong, stable magnetic field. This field aligns the protons in the body's water molecules. Radio waves are then used to systematically alter the alignment of this magnetization, causing the protons to produce a rotating magnetic field detectable by the scanner. This information is used to create detailed images of organs, tissues, and bones without using invasive surgery.
5. Why does a freely suspended magnet always point in the North-South direction?
A freely suspended magnet aligns itself in a North-South direction because the Earth itself behaves like a giant bar magnet. The Earth has its own magnetic field with a magnetic North and South pole. The north pole of a magnet is attracted to the Earth's magnetic south pole (which is near the geographic North Pole), and the magnet's south pole is attracted to the Earth's magnetic north pole. This is known as the directive property of magnets and is the principle behind the magnetic compass.
6. How do magnets play a role in computer data storage?
Magnets are crucial for data storage in devices like hard disk drives (HDDs). The surface of the disk is coated with a magnetic material, which is divided into billions of tiny areas. An electromagnetic head writes data by magnetising these tiny areas in one of two directions, representing a binary bit (a 1 or a 0). To read the data, the head detects the magnetic direction of each area, translating it back into digital information.
7. Can a permanent magnet ever lose its magnetism? If so, how?
Yes, a permanent magnet can lose its magnetism. This process, called demagnetisation, can happen in three main ways:
- By Heating: If a magnet is heated above a specific point known as its Curie temperature, the thermal energy disrupts the alignment of its magnetic domains, causing it to lose its magnetism permanently.
- By Mechanical Shock: Dropping or striking a magnet with force can knock its internal magnetic domains out of alignment, weakening its overall magnetic field.
- By Opposing Magnetic Fields: Exposing a magnet to a strong magnetic field with the opposite polarity can reverse or scramble its domain alignment, thereby demagnetising it.
8. What are the three fundamental properties of any magnet?
Every magnet exhibits three fundamental properties:
- Attractive Property: A magnet attracts ferromagnetic materials such as iron, cobalt, and nickel.
- Repulsive Property: Like magnetic poles (North-North or South-South) repel each other, while opposite poles (North-South) attract each other.
- Directive Property: When suspended freely, a magnet will always align itself in a geographical North-South direction, which is the basis for the compass.
9. If magnets attract iron, why isn't a small fridge magnet strong enough to pull a heavy iron object from across the room?
This is because a magnetic field's strength decreases very rapidly with distance. The force exerted by a small fridge magnet is only strong enough to affect objects it is very close to or touching. For an object far away, like an iron chair, the magnetic force becomes too weak to overcome other forces like friction and inertia (the chair's weight). The magnet's field simply does not extend far enough with sufficient strength to have a noticeable effect.
