Question

In the field of electromagnetism, the term “EMI” stands for:
A) Electromotive impact
B) Electromagnetic induction
C) Electromotive inertia
D) None of these

Answer 1

Hint:The term “electromagnetism” stands for the study of the interaction between magnetic and electrical forces. And the term electromagnetic induction means the induction of electromotive force under the influence of magnetic field.

Step by step answer:
Electromagnetism encapsulates the study of the interaction of electrical and magnetic forces. This includes the study of electrical force induction in the presence of magnetic force.

Electromagnetic induction is the phenomenon by which current is generated in a coil due to the change in the magnetic flux in association with it. Similarly, current is also induced in the circuit or coil when the direction of the current I changed when it’s in the span of a magnetic field.

The first method of current induction is adopted in DC inverters while the second method is used in case of AC generators.

Electromagnetic induction was first studied by Michael Faraday in 1980. Based upon his observations, he produced two laws known as “Faraday’s Laws of Electromagnetic Induction”:

1) Change in magnetic field of a wire will induce an electromotive force (emf) in it. This emf is called “induced emf”.

2) Rate of change of flux is equal to the induced emf.

Mathematically,
$E = - N\dfrac{{d\phi }}{{dt}}$
Where $E$ is the induced emf and is expressed in Volts $(V)$, $N$ is the number of turns in the coil, $\phi $ is the magnetic flux and is expressed in Webers $(W)$, $t$ is the time taken for the flux change and is expressed in seconds $(s)$.

In conclusion, the answer is option B.

Note: electromotive impact and inertia are imaginary quantities. They do not exist. The only proper answer in this particular question is EMI.