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. Simply put, an electromagnet is a magnet which functions on electricity. 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 are Electromagnets?
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.
Working Principle of Electromagnets
So how does this work? Let’s consider the iron nail itself. Why does it not produce a magnetic field when not influenced by an electric field? What changes?
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.
Uses of Electromagnets
- Particle Accelerators
- Magnetic Separation
- Electric Motors and Generators
- MRI machines
- Control Switches in Relays
- Spacecraft Propulsion Systems
- Induction Heating
- Hard Drives
Electromagnetism is one of the fundamental phenomena in nature. But why do we study electricity and magnetism separately? Learn Physics the right way with BYJU’S.
Playing with twisty puzzles is the best way of improving your dexterity and problem-solving skills.
Q1) What is 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.
Q2) Which of the following is not a part of electromagnets?
- Power source
Answer: a. Toothpick
Q3) List a few uses of electromagnets.
Following are a few uses of electromagnets:
- Particle accelerators
- Hard drives
- Electric Motors and generators
Q4) If a magnet is split into half, one ends up with only a north pole on one magnet and South pole on another
Answer: b. False
One ends up with two magnets with both north and south pole on each.
Q5) Which of the following is true of magnets?
- North and South Pole repel each other
- North and North pole attract each other
- Statement 1 is true
- Statement 2 is true
- Both 1 and 2 are true
- Both 1 and 2 are false
Answer: d. Both 1 and 2 are false
Like poles repel each other and unlike poles attract each other.
Q6) List a few 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
Q7) The force of attraction in a magnet is strongest at its _____.
The force of attraction is strongest in a magnet at its pole.
Q8) List a few 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