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Bar Magnet as an Equivalent Solenoid

Last updated date: 16th May 2024
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Solenoid Equivalent to a Bar Magnet

It is important to understand what a bar magnet is and what a solenoid is as well as their similarities and differences in order to truly appreciate how a bar magnet is equivalent to a solenoid. We will learn how a bar magnet is equivalent to a solenoid in this article.

What is a Bar Magnet?

In magnetism, a bar magnet is made up of two poles, north and south, in a rectangular or square object made out of iron or steel.


Natural magnets and artificial magnets are two types of magnets. They are manufactured by humans. They are:

  1. Natural Magnets: These magnets exist naturally and possess weak magnetic fields. Lodestones are an example of natural magnets.

  2. Artificial Magnets: They are designed by humans. Their magnetic fields are stronger. They can be customized in any way. Magnets shaped like bars are called bar magnets.

What is Solenoid?

The solenoid is an electromagnet used to generate controlled magnetic fields through electric current passing through a coil with a length greater than diameter.

How Does It Work?

In the same way as other magnets, solenoids with an activated magnetic field have positive and negative poles. A magnetic solenoid has a negative end that attracts and a positive end that repels. With each forward and backward motion of the piston, an electromagnetic field is produced inside the solenoid.

What is the Use of Solenoid?

  • A solenoid is used in an automobile's ignition system. 

  • Solenoid relays are used for bringing metals together. 

  • Due to their versatility, solenoids are extremely useful. 

For instance, they can be used for:

  • Activating doorbells.

  • Activating paintball guns on automatic factory machines.

  • Activating a doorbell chime.

Bar Magnets and Solenoid Similarities

Bar magnets and solenoids have some similarities:

  1. Attractive and directive properties are shared by both magnets. 

  2. These magnets can be aligned with the external magnetic field.

  3. Their axial fields are identical.

  4. Their magnetic moments are also identical.

Solenoid vs. Bar Magnet:

  • Magnets are permanent while solenoids are electromagnets, which means that they will act as magnets only if an electric current is applied.

  • The same magnetic properties are shared by both pieces of a split bar magnet, while the magnetic fields of a split solenoid are weaker.

  • In contrast to a solenoid, the poles of the bar magnet are adjustable.

  • Unlike a bar magnet, the magnetic field of a solenoid is affected by the electric current which passes through it, while the magnetic field of a bar magnet is unaffected by the current.

What is the Behavior of a Solenoid?

How can a bar magnet be used to determine the north and south poles of a current-carrying solenoid? 


  • The solenoid consists of a coil of insulated copper wire wound in circular loops. When current flows through a solenoid, magnetic field lines are created around it. This device produces a magnetic field similar to that produced by a bar magnet.

  • Bringing the north pole of a bar magnet near the negative terminal of a battery repels the bar magnet as the solenoid is powered.

  • According to the principle of like poles repelling each other, the end of the solenoid connected to the negative terminal of the battery acts as the North Pole of the device, and the other end acts as the South Pole. In this sense, one end of the solenoid represents the North Pole, while the other end represents the South Pole.

Natural Magnets or Artificial Magnets are Stronger: which is Stronger?

The magnetic field of an artificial magnet is quite stronger than that of a natural magnet. Natural magnets do not have the ability to alter their magnetic field. An artificial magnet, on the other hand, can develop a stronger magnetic field by adding more coils or increasing current flow.

FAQs on Bar Magnet as an Equivalent Solenoid

1. How does the Magnetic field generate artificially?

Electric current is the agent to initiate the artificial magnetic field. It happens because of the motion of electric current through the wire. The surrounding of the wire turns into a magnetic field, and the strength is too high than natural magnets.

2. Does the Magnetic field of earth decrease? Explain.

The reason is still unknown, scientists have indeed noticed the weakening of the magnetic of the earth. The region from Africa to South America has sensed a decline in the magnetic field. So, it is decreasing gradually as per the scientific view.

3. State that an Electromagnet is a permanent magnet.

The electromagnet is made from wires tied in a circular fashion. We can say it as a coil of wire. When current passes through the wire, the magnetic field is induced to the coil, and when we disconnect it, the coil shows no magnetic field. This means an electromagnet is not a permanent magnet.

4. Which Magnet is stronger: A Natural Magnet or an Artificial Magnet?

An artificial magnet is quite stronger than that of a natural magnet. The reason is we can’t alter the magnetic field available in a natural magnet. However, in the case of an artificial magnet, the increase in the number of coils or raising the current flow can develop a stronger magnetic field.

5. Do bar magnets act as electromagnets? Where do bar magnets occur in nature?

Electromagnets are not bar magnets. Bar Magnets are permanent magnets that have a persistent magnetic field, while electromagnets are temporary magnets that generate a magnetic field when subjected to an electric current.

Magnets made from natural materials include bars, horseshoes, disks, and refrigerator magnets. On beaches, magnetite usually contributes to the black sand. Compass makers used lodestone to make the Chinese compass.

6. What are the types of magnets?

The following are the types of magnets:

  • Permanent magnet

  • Temporary Magnet

  • Electromagnets

7. Write some of the uses of electromagnets.

Electromagnets are used for:

  • They’re used in electric bells and buzzers, speakers and motors.

  • Among the applications of electromagnets are relays, motors, generators, and transformers.

  • They are also used in MRI machines.

8. What are the different types of bar magnets?

Bar magnets come in two types:

  • Cylindrical bar magnet: A cylindrical rod magnet is also known as a rod magnet because it has a thickness that is equal to or greater than its diameter. Research, education, and experimental uses are applicable to these bar magnets.

  • Rectangular bar magnet: Rectangular bar magnets have greater magnetic field and strength than other magnets, making them suitable for manufacturing and engineering applications. 

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