Courses
Courses for Kids
Free study material
Offline Centres
More
Store Icon
Store

Unit of Inductance

ffImage
Last updated date: 29th Mar 2024
Total views: 419.4k
Views today: 9.19k
hightlight icon
highlight icon
highlight icon
share icon
copy icon

What is Inductance?

The attribute of a current-carrying closed-loop that causes an electromotive force to be generated or induced by a change in the current flowing via it. Such an attribute is called the inductance.


On This Page, We'll Learn About the Following:

  • Inductor unit

  • Inductance unit

  • S.I. unit of inductance

  • What is the si unit of inductance?


Inductor

An inductor is a coil of wire cloaked around a magnetic material.


Current flowing via the inductor generates a magnetic field that does not change, as it is trying to oppose the change in the flow of current which means the current flow remains constant inside the inductor. 


The inductor won’t generate any forces on the charged particles flowing via it. In such a case, the inductor just behaves like a normal wire.


The current flow is opposed by the resistance, and the time comes when there comes a 

current decay (decline). The larger the resistance, the faster the current will decline.


On the other hand, the larger the inductance of the inductor, the slower the current will decay.


What is Inductance?

The inductance is the ability of an inductor or any current-carrying conductor to oppose the change in the current flowing through it. The inductors do this by generating a self-induced emf within itself (Faraday’s law of induction) as a result of their changing magnetic field. 


S.I. Unit of the Inductor

The S.I unit of the inductor is Henry H


MKS unit is Kg m² s⁻² A⁻²


Where one Henry is equal to the one-kilogram meter squared per second squared per ampere squared.


(Image will be uploaded soon)


What is Self - Inductance?

Inductance is also called self-inductance. When a current is established in a closed conducting loop, it creates a magnetic field. This magnetic field has flux produced in an area of the closed-loop. If the current varies with time, the flux via the loop also changes. Hence an EMF is induced in the loop. Such a process is called self-induction.


The magnetic field at any point due to current is proportional to the current. The magnetic flux in an enclosed area of the conductor can be represented as,


φ  ∝ i  ⇒ φ = L i


Where L is a proportionality constant and is called the coefficient of self-inductance or simply self-inductance of the loop.


(Image will be uploaded soon)


The inductance in the coil (Fig.1) depends on the number of turns, area of cross-section, and nature of the material of the core on which the coil is wrapped.


If i =1,  φ = L x i  or  L = φ


Therefore, the coefficient of self-inductance is numerically equal to the amount of magnetic flux linked with the coil when unit current flows through the coil.


From Faraday’s law of induction, any variation in the magnetic field generates emf, given by,


E =  -  dφ (t) / dt  = - L di / dt


The negative sign indicates that the changing current induces a voltage in the conductor and this induced voltage is in a direction that tends to oppose the change (increase or decrease) in the electric current (Lenz’s law) is called the back EMF.


Inductance for a Long Solenoid

The inductance of a solenoid is given by,


B = μ₀ N I / L


The magnetic flux density can be obtained by multiplying the B with cross-sectional area A, we get,


φ = B xA = μ₀ N x i x A / l….(1)


Since total magnetic flux inside the coil = flux via each turn x total number of turns. 


φ = B xA = μ₀ N x N i x A / l….(2)


Where μ₀ is the magnetic constant or absolute magnetic permeability of free space/air forms the core of the solenoid.

  • N = The total no of turns of the solenoid

  • i = The current 

  • l = The length of the solenoid

  • A = Area of each turn of the long solenoid


We know that


φ  = L i….(3)


From (2) and (3) we get,


L i =  μ₀ N x N x A xi / l x N we get,


L = μ₀ N² x A/ l


μ = μ₀ . μr


When the core is of any other magnetic material μ₀ is replaced by 

μr (relative magnetic permeability).


Here, we Conclude the Following Things,

  • L increases with the number of turns in the coil.

  • It depends on the magnetic permeability of the material.

  • The cross-sectional area.

  • L is independent of the current.


S.I. Unit of Inductance

The S.I. unit of self-inductance is weber/ ampere or volt-second/ ampere. 

It is also denoted by Henry (H), named after an American scientist named Joseph Henry. 

Where Henry is the amount of inductance that generates a change of one volt and when the current is varying at the rate of one ampere per second.


Note: All conductors have some inductance, which may have either desirable or detrimental effects in electrical circuits and it depends on the geometry of the current path and on the magnetic permeability of the materials.


The ferromagnetic material tends to have a high inductance because of the flow of large amounts of electric flux (total magnetic field) through the conductor produced by a current flowing through it increases the inductance in that conductor.


Inductor Working Principle

When ac current is applied to the inductor coil, its own current changes, causing its own magnet to change, creating an electromotive power. This condition is called self-inductance. The direction of the self-induced current is always affected. When the alternating current increases, the direction of the self-inductance current is opposite to that of the AC current. When the AC current is weak, the direction of the self-inductance current is the same as that of the alternating current, which has a blocking effect.

  • Self-Induction- When the current flows into the coil, a magnetic field is produced around the coil. As the current in the coil changes, the surrounding magnetic field also changes accordingly. This change in a magnetic field can cause the coil itself to generate electromotive energy (EMF is used to represent the terminal voltage of the active power of the active components).

  • Mutual Inductance- If two coils of an inductor are close together, the magnetic field conversion of one coil will affect the other, and this effect is mutually beneficial. Its size depends on the degree of interaction between self-inductance and the two coils. The components formed by this policy are called mutual inductors.


Factors affecting Inductance in a Circuit

The following factors affect inductance in a circuit

  • The Number of Wires Transforming into Coil - The greater the amount of cable twist on the coil, the greater the inductance. Slight twisting of the cable to the coil results in a small inlet. Most cable coils show a large amount of magnetic field in a given number of current coils.

  • Coil Location - The larger the coil area, the greater the inductance. The location of the small coil leads to the small entrance. The large coil area exhibits minimal resistance to the formation of magnetic field flux, with a given amount of field strength

  • Material of the Coil - The greater the magnetic field of the core where the coil is wrapped, the greater the reach; less contextual access reduced inductance.

  • Length of the Coil - When the coil length is longer, the inductance decreases. The shorter the coil length, the greater the inductance.


Summary

With the change in the magnetic flux, induced emf is a must, but induced current will only appear only when the circuit is closed.


An Inductor is equivalent to a short circuit to DC, because once the storage phase has been completed, the current, i, that flows through is stable, no emf is induced. So the inductor behaves like a normal wire where Resistance R is zero

FAQs on Unit of Inductance

1. What Factors Affect Coil Inductance?

The passive two-terminal electrical component that leads to the storage of energy in a magnetic field during which the current flows through it is called the inductor which is also known as the coil, choke, or reactor. There are multiple physical factors that affect the inductance of a coil. 

  • The number of turns and the number of layers of winding in the coil.

  • The diameter of the coil

  • The length of the coil

  • The type of material used

  • Area of each turn of the coil

2. What is the Function of an Inductor in an AC Circuit?

Inductors block the flow AC current and the inductors designed for this purpose are called chokes but allow the DC flow because the physical attribute is to resist sudden changes in the current. They are used in electronic filters to divide signals of varying frequencies and in combination with capacitors, they are used to tune radio and TV receivers. Inductance is a good method of putting a limit on the rate of change of current, which is a very good thing if the motive is to filter out voltage or variations of current. It stores its energy in the form of a magnetic field which is created when the voltage is applied through various terminals of an inductor.

3. How do I download the SI Unit of Inductance, Inductor, and FAQ study material?

It is not a strict and quick rule that you need to follow the steps regarding downloading study material. Vedantu teachers have developed some very useful notes that will help you to read the whole chapter and the concept of walking distance. All of this is readily available on the Vedantu website which contains many other reading materials. You just need to sign in to the website and you will get a systematic set of results. Choose between them and start your journey towards different learning.

4. What will you get when you study SI Unit of Inductance, Inductor, and FAQ from Vedantu?

You will definitely love the learning pattern that Vedantu professional teachers have introduced to students. You do not need to find anything else after reading this website:

  • It is written in simple, easy-to-understand language.

  • Basic concepts are included in the solutions to

  • Students' time and effort are saved by moving to the market and buying expensive books

  • 100% authentic solutions provided by Vedantu experts

  • It builds on students' cognitive knowledge and helps to build a better understanding

5. Why is Vedantu a reliable website for downloading the material?

Yes, the students can perfectly trust Vedantu as the best online website for downloading the study material for SI Unit of Inductance, Inductor, and FAQ. The experts at Vedantu have designed these solutions keeping in mind the analytical skills and creative minds of the learners and people who are keen to learn new things. The topic, SI Unit of Inductance, Inductor, and FAQ, is a very interesting topic which needs 100% attention as it will definitely concern the physics students. So, therefore the students must take the necessary steps to download the engaging study material.

Students Also Read