## Question & Answer on Magnetic Circuit for Interview & Exam

1 - How to know the Direction of Magnetic Field?
The Direction of Magnetic Field can be Obtained by using Right Hand Thumb Rules, Where Thumb show the Direction of Current and Folding Fingers Show the Direction of Magnetic Field.

2 - What is Magnetic Flux?
It is the Number of Magnetic Field lines passing through a Normal Cross section area in a Magnetic Field.

It is Define as the dot Product of Magnetic Field Density (B) with Area Vector (A).

ϕ = B.A = BA Cosθ

S.I. Unit = Weber

If θ=0, ϕ Will be Max
If θ=90, ϕ Will be Min

3 - What is Magnetic Motive Force (MMF) in Electrical Engineering?
It is Responsible to Generate Magnetic Flux in Magnetic Circuit. It is Define as Product of Current Flowing in a Coil and Number of Turn of the Coil.

Magnetic Motive Force (MMF) = NI

S.I. Unit = Amp-Turn

4 - What is Reluctance in Magnetic Circuit?
It is Property of Magnetic Material which Opposes the Flow of Magnetic Flux.

F = Rϕ So R = F/ϕ

S.I. Unit = Amp-Turn/Weber

5 - What is Permeance in Magnetic Circuit?
It is Opposit of Reluctance.

Λ = 1/R

S.I. Unit = Weber/Amp-Turn

6 - What is Magnetic Field Intensity (H)?
Magnetic Field Intensity Define as Magnetic Motiv Force(MMF)/Unit Length

H = MMF/L

S.I. Unit = Amp-Turn/Meter

7 - What is Self Induction?
Self Induction is the Property of coil which opposes any change in the current of the coil. It is Define as Linkage Flux/Unit Current.

L = Nϕ/I

S.I. Unit = Henry

8 - What is Mutual Inductance?
When the two coils are placed very near to each other and the flux of coil one also link to coil two then the induction known as Mutual Induction.

9 - What is Coupling Coefficient?
Coupling Coefficient Define as the Ratio of Mutual Induction to the Gematrical Mean of two Induction. (√L1L2)

K = M/√L1L2

Note -
1 - If K=1, It means 100% Coupling.
2 - If K>0.5 it means Tightly Coupling.
3 - If k<0.5 it means Loosely Coupling.

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#Interview question on magnetic circuit
#Important question on magnetic circuit
#basic of magnetic circuit