NEET Self and Mutual Inductance Difference between
Introduction:
Inductance is a property that basically explains how a circuit element, for instance, a coil or a solenoid can induce an electromotive force (EMF) against changing current within it. Inductance is very significant in many applications that vary from power transmission systems and distribution to the operation of electronic devices. Ever wonder how an MRI machine could possibly achieve such high-resolution images of all the innards? Well, self and mutual inductance play a role here. The creation of powerful magnetic fields by the MRI machine works along the principles of inductance to create images helpful in medical diagnoses. In this application of inductance, it becomes possible to demonstrate its relevance in the medical field. It is even possible to gaze inside the human body and diagnose ailments precisely.
Self Inductance:
This is the property of a component such as a coil or a solenoid to exert an opposing force within itself when the electric current flowing through it changes. It arises from the effect of the switching current interacting with the magnetic field that it has produced. The unit for measuring the magnitude of self-inductance is henries (H), and it depends upon the geometry of the component, the number of wire turns within a coil, and the properties used in constructing a coil.
Amongst the applications of self-induction are tuning circuits, inductor relays, sensors, ion motors, and transformers.
Mutual Inductance:
Mutual inductance is that interaction of two different circuits which are placed near each other. When the current of one circuit changes, it creates a changing magnetic field. This changing magnetic field is coupled with the nearby circuit and, thus, induces a voltage within the coils. Mutual inductance is measured in henries (H).
This is referred to as mutual inductance because it demonstrates how the changing magnetic field that one coil generates influences the behavior of the neighboring coil. Thus, study of mutual inductance provides insight into the subtle interdependence between magnetic fields and electrical currents, deepening our understanding of how electromagnetic phenomena interact in nature and in science and technology.
Applications of mutual inductance include transformers, pacemakers, digital signal processing, electric cloth dryers, coil balancing, and metal detectors at airports.
Mathematical Form of Inductance:
Since it is evident that inductance is a property of material, it depends only on the dimensions of material, which are the length, area of cross-section, number of turns, and the permeability of free space.
The Mathematical form of Self Inductance:
The self-inductance of a coil or inductor is given by the equation:
L=μ∘N2AlL=μ∘N2Al
where:
L is the self-inductance in Henry (H).
μ∘μ∘ is the permeability of free space (approximately 4π×10−74π×10−7 H/m).
N is the number of turns in the coil.
A is the cross-sectional area of the coil’s core.
ℓ is the length of the coil’s core.
The Mathematical form of Mutual Inductance:
The mutual inductance between two coils, typically denoted as Coil 1 and Coil 2, is expressed as
L=μ∘N1N2AlL=μ∘N1N2Al
where:
M is the mutual inductance in Henry (H).
μ∘μ∘ is the permeability of free space.
N₁ is the number of turns in Coil 1.
N₂ is the number of turns in Coil 2.
A is the area shared by the two coils’ magnetic fields.
ℓ is the distance between the coils.
Difference Between Self and Mutual Inductance:
Self-inductance is a property of a component by itself, whereas mutual inductance is an interaction between two independent circuits or coils. It depends on the geometry and materials for self-inductance, but it will depend on the proximity and orientation of circuits or coils for mutual inductance.
The other difference is shown in the below table:
|
Self-Inductance |
Mutual Inductance |
| Self-inductance refers to the property of an electrical component, such as coil, to generate an opposing electromotive force (EMF) when the current passing through it changes. | Mutual inductance refers to the interaction between 2 separate electrical circuits, where a changing current in one circuit induces an electromotive force (EMF) in the other circuit. |
| Self-inductance occurs with in single component due to the interaction between the changing magnetic field produced by the current and the component’s own turns of wire. | Mutual inductance occurs when the a magnetic field produced by one circuit links with the other circuit. |
| It opposes changes in the current flowing through on the component. | It transfers energy between the two circuits and can results in voltage and current changes in the secondary circuit. |
| Self-inductance is represented by in the symbol ‘L’. | Mutual inductance is represented by in the symbol ‘M’. |
| The unit of self-inductance is Henry (H). | The unit of mutual inductance is Henry. |
Self and Mutual Inductance Reaction
Self-inductance and mutual inductance are phenomena observed in electrical circuits due to the presence of inductor or coils. Let’s explore the reactions associated with self-inductance and mutual inductance:
Self-Inductance Reaction:
Self-inductance occurs within a single coil or inductor when the current passing through it change. The reaction to changes in current in a self-inductor is as follows:
- Resistance to Change Any change in the current flowing through the coil develops an opposing electromotive force.
- Induced EMF: Self-induced EMF in a coil is a tendency to oppose the change causing it. Lenz’s law describes the phenomenon, where induced EMF in a coil opposes the change in current.
- It stores energy in the magnetic field set up by the time-varying current; it opposes changes in the current and the stored energy will be released back when the current falls.
Mutual Inductance Reaction:
Mutual inductance occurs when two independent coils, known as primary and secondary coils, are brought close to each other. The response of changes in current in the primary coil to modify the conditions in the secondary coil is given by:
- Induced EMF: The changing magnetic field produced due to variation in the primary coil current induces an electromotive force in the secondary coil.
- Energy Transfer: This implies that one coil can transfer energy to the other coil. Mutual inductance occurs when a change in current through one coil produces a changing magnetic field, which in turn induces a corresponding voltage in the other. Therefore, mutual inductance enables the transfer of electrical energy.
- Step-Up and Step-Down: Mutual inductance is applied in transformers in order to step up or step down the levels of electrical energy. Transformers transfer electrical power efficiently at different levels of voltages by simply changing the turns in the primary and secondary coils.
Some of the examples of self-inductance and mutual inductance reactions are: There is a vast use of self-inductance and mutual inductance reaction examples in many devices. Both of them have significant contributions in the study of the behaviour of inductors and other electromagnetic devices. These reactions show the interlinking characteristic of changing currents, magnetic fields, and induced EMFs in determining the operational behaviour of electric circuits, which further allows energy to flow in many applications.
Summary:
What is self-inductance and mutual inductance reaction? Now this understanding is very much necessary for the students. Self-inductance: It is the property by which single component opposes changes in the current flowing through that particular component. Mutual induction: There is an interaction of two different circuits, which causes an electromotive force in other circuit when changes take place in first circuit. Some of the concepts finally culminate into practical applications, like energy storage in inductors and energy transmission through transformers. By knowing the difference between self and mutual inductance, the foundations in electromagnetism will be strong for NEET aspirants so that they would be capable of applying their knowledge to practical problems arising in electrical engineering.
