Induction is a basic principle of physics, which concerns the generation of electric current or voltage by a changing magnetic field. It is important for many applications in practice such as electric generators, transformers, or inductive charging systems. Understanding induction explains why many of the things used on a day-to-day basis including home appliances, electric cars and many others, work efficiently. This article focuses on the definition, their differences, and induction questions. Therefore, their significance in today’s world will be easier to appreciate.
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Inductance refers to an electrical conductor’s capability to withstand the changes in electric current passing through it. L is the symbol to represent inductance and its SI unit is Henry. One Henry is defined as the quantity of inductance whereby an induced emf of 1 volt appears in a coil of wire carrying out a change in current of 1 ampere/second.
Types of Inductance
Inductance is classified into two types:
Self Induction
Mutual Induction
The electromotive force is created whenever there is a variation in either the electrical current or the magnetic flux of the coil. Such a process is known as Self-Inductance. At any instant when the current begins to increase in the coil, the magnetic flux is found to vary directly with the current in the circuit. The relationship is expressed as:
$$
\phi=L \times I
$$
Where $L$ is termed as the self-inductance of the coil or the coefficient of self-inductance, the self-inductance depends on the cross-sectional area, the permeability of the material, and the number of turns in the coil.
The rate of change of magnetic flux in the coil is given as,
$$
\begin{aligned}
& e=-\frac{d \phi}{d t}=-\frac{d(L I)}{d t} \\
& e=-L \frac{d I}{d t}
\end{aligned}
$$
$$
L=N \frac{\phi}{T}
$$
Where,
Lis the self-inductance in Henries
N is the number of turns
$\Phi$ is the magnetic flux
I is the current in amperes
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Let us consider two coils. The first coil will be referred to as the P- coil (Primary coil) and the second will be is S- coil (Secondary coil). A battery and a key are connected to the P-coil, while a galvanometer is connected across the S-coil. Whenever there is a change in the provided current or the magnetic flux associated with both coils, then in each coil an electromotive force appears which opposes the change, this is called Mutual Inductance.
This phenomenon is given by the relation:
$$
\phi=M I
$$
Where $M$ is termed as the mutual inductance of the two coils or the coefficient of the mutual inductance of the two coils.
The rate of change of magnetic flux in the coil is given as,
$$
\begin{aligned}
& e=-\frac{d \phi}{d t}=-\frac{d(M I)}{d t} \\
& e=-M \frac{d I}{d t}
\end{aligned}
$$
$$
M=\frac{\mu_0 \mu_1 N_1 N_2 A}{l}
$$
Where,
$\mu_0$ is the permeability of free space
$\mu_r$ is the relative permeability of the soft iron core
N is the number of turns in the coil
$A$ is the cross-sectional area in $\mathrm{m}^2$
I is the length of the coil in $m$
Self-induction | Mutual induction |
is the coil's self-inductance. | The mutual inductance of a pair of coils is its characteristic. |
When the coil's main current decreases, the induced current opposes the decay of the coil's current. | If the coil's main current decreases, the induced current developed in the neighbouring coil opposes that decline. |
Whenever the coil's main current increases, the induced current opposes it. | A neighbouring coil develops induced current when the main coil's current increases and this impedes the coil's growth. |
Also read :
Consider a DC source. When the switch is turned on, the current flows from zero to a certain value such that there is a change in the rate of current flowing. Let $\phi$ be the change in flux due to current flow. The change in flux is with respect to time which is given as:
$$
\frac{d \varphi}{d t}
$$
Apply Faraday's law of electromagnetic induction,
$$
E=N \frac{d \phi}{d t}
$$
Where,
N is the number of turns in the coil
E is the induced EMF across the coil
From Lenz's law, we can write the above equation as
$$
E=-N \frac{d \phi}{d t}
$$
The above equation is modified for calculating the value of inductance
$$
\begin{aligned}
& E=-N \frac{d \phi}{d t} \\
& E=-L \frac{d i}{d t}
\end{aligned}
$$
Henry is the SI unit of inductance.
One Henry is defined as the amount of inductance required to produce an emf of one volt in a conductor when the current change in the conductor is at the rate of One Ampere per second.
Inductance is affected by the following factors:
A measure of how many turns is in the wire of the inductor.
the core material used.
The shape of the core.
There is an opposite induced electromotive force when there is a change in current or magnetic flux in the coil. Self-Induction is the phenomenon responsible for this behaviour. The magnetic flux is directly proportional to the current passing through the coil when the current starts flowing through it at any time.
Mutual Induction Definition: It is necessary to place two coils near each other. Coils P and S refer to primary (primary coil) and secondary (secondary coil) coils, respectively. With the P-coil, a battery and a key are attached while with the S-coil, a galvanometer connects across it. An opposing electromotive force is produced across each coil when the current or magnetic flux varies between two coils, and this phenomenon is called Mutual Induction.
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Correct Answer: Employee benefits
Solution : The correct answer is (c) Employee benefits
LMN Enterprises plans to attract seasonal employees by offering incentives such as bonuses and flexible working hours. This strategy is related to employee benefits, as these perks are part of the overall compensation package designed to attract and retain candidates. In this context, the organization is using attractive benefits to make the temporary positions more appealing to potential seasonal employees.
Correct Answer: Outsourcing training
Solution : The correct answer is (d) Outsourcing training
When the HR manager at PQR Inc. decides to use external consultants to provide specialized training to employees for their new roles, the strategy being employed is outsourcing training. Outsourcing training involves hiring external experts or consultants to deliver specific training programs or sessions to employees, leveraging external expertise to meet the organization's training needs. This approach is common when organizations seek specialized knowledge or skills that may not be available internally.
Correct Answer: Employee benefits
Solution : The correct answer is (c) Employee benefits
LMN Enterprises plans to attract seasonal employees by offering incentives such as bonuses and flexible working hours. This strategy is related to employee benefits, as these perks are part of the overall compensation package designed to attract and retain candidates. In this context, the organization is using attractive benefits to make the temporary positions more appealing to potential seasonal employees.
Correct Answer: Statement 1 is false and statement 2 is true.
Solution : The internal source of recruitment prevents induction of fresh talent. By stopping in fusion of new blood into the organisation it may also lead to in breeding that is existing employees may continue to work and behave in old ways even after promotion and transfer.
Hence, option D is correct.
Correct Answer: The assertion is true, but the reason is false.
Solution : The correct answer is (c) The assertion is true, but the reason is false.
The assertion is true. Induction programs are indeed designed to familiarize new employees with the organization, its culture, policies, and procedures.
The reason is false. Induction is not primarily focused on testing technical skills; instead, its primary focus is on providing information and support to help new employees integrate into the organization effectively.