We already know that an electric current has the ability to produce a magnetic field in a plane perpendicular to the direction of current flow. The electromagnet uses this principle. An electromagnet can be defined as a magnet which functions on electricity. Unlike a permanent magnet, the strength of an electromagnet can be changed by changing the amount of electric current that flows through it. If the current flow is cut, the property of magnetism ceases to exist.
But this is also an advantage of the electromagnet over a permanent magnet because controlling the electric current also controls the magnetic field, in this case, i.e., the strength of electric field controls the strength of magnetic field also. In fact, the poles of an electromagnet can even be reversed by reversing the flow of electricity.
What is Electromagnet?
Electromagnets are made out of a coil of wire (wire curled in series). This is more effective in producing a magnetic field than just a wire running straight. This effect can be strengthened by winding a wire tightly around a powerful core, made of magnetic material, such as iron. The picture above shows a coil wound around an iron nail. On its own, the iron nail is not magnetic.
Properties of Magnet
A few properties of the magnet are as follows:
- Attractive Property – Ferromagnetic materials like iron, nickel and cobalt are attracted by magnets
- Repulsive Property – Like poles repel each other while unlike poles attract each other
- Directive Property – A freely suspended magnet always points in the north-south direction
Working Principle of Electromagnets
So how do electromagnets work? Let’s consider the iron nail itself. Why does it not produce a magnetic field when not influenced by an electric field?
An iron nail made into a magnet by passing electric current through a coil surrounding it.
Normally, the atoms in the nail are oriented in random directions and individual magnetic fields cancel each other out. Under the influence of electric current, these atoms are reoriented to start pointing in the same direction. All these individual magnetic fields together create a strong magnetic field. As the current flow increases, this degree of reorientation also increases, resulting in a stronger magnetic field. Once all the particles are reoriented perfectly in the same direction, increasing current flow will not affect the magnetic field produced. At this point, the magnet is said to be saturated.
You may also want to check out these topics given below!
- What is a Magnet?
- Poles Of Magnets
- Uses of Magnets
- Electricity and Magnetism
- Magnetic Effect of Electric Current
Uses of Electromagnets
Some electromagnet uses are given in the points mentioned below:
- Particle Accelerators
- Amplifiers
- Magnetic Separation
- Electric Motors and Generators
- MRI machines
- Control Switches in Relays
- Transportation
- Spacecraft Propulsion Systems
- Induction Heating
- Hard Drives
Disadvantages of Electromagnetism
A few disadvantages of electromagnetism are as follows:
- They heat up very fast
- It consumes a lot of energy
- They can store huge amounts of energy in their magnetic field. If the electric current is interrupted, the energy will discharge
Electromagnetism is one of the fundamental phenomena in nature. Learn more physics concepts with the help of interactive video lessons by visiting BYJU’S.
Frequently Asked Questions on Electromagnet Questions
What is the principle of an electromagnet?
A magnet that consists of a piece of iron or steel surrounded by a coil is known as an electromagnet. When an electric current is passed through the coil, the metal becomes magnetic.
The force of attraction in a magnet is strongest at its _____.
Poles
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Please tell me about flux gate magnetic sensor used in aircraft for finding heading
A fluxgate magnetometer consists of a small magnetically susceptible core wrapped by two coils of wire. The core is driven through an alternating cycle of magnetic saturation by passing an alternating electric current through one of the coils. The constantly changing magnetic field induces an electric current in the second coil. In a magnetically neutral background, the input and output currents match. However, when the core is exposed to a background field, the core is easily saturated in alignment with the background field and less easily saturated in opposition to it. Hence the alternating magnetic field, and the induced output current, are out of step with the input current. The extent to which this is the case depends on the strength of the background magnetic field.