Correct Answer - Option 3 : reluctance
Concept:
Reluctance opposes the passage of magnetic flux lines. Reluctance is analogous to resistance.
We can define the reluctance as,
\(\Re = \frac{{mmf}}{{flux}}\)
We know that, \(H = \frac{{NI}}{l}\)
Where H is field strength
N is the number of turns in a coil
l is mean length of flux in a magnetic circuit
I is current through the coil
The flux in a magnetic circuit is given by
\(\phi = BA\)
\(= \mu HA\)
\(= \mu \left( {\frac{{NI}}{l}} \right)A\)
\(\Rightarrow \phi = \frac{{NI}}{{\frac{1}{\mu }\frac{l}{A}}} = \frac{{mmf}}{{reluctance}} = \frac{{mmf}}{\Re}\)
Now, we can define reluctance as \(\Re = \frac{l}{{\mu A}} = \frac{l}{{{\mu _0}{\mu _r}}A}\)
Important Points:
Impedance(Z) is given by Z = R + jX
Where,
Z = Impedance in Ohm
R = Resistance in Ohm
X = Reactance in Ohm
Then Admittance(Y) can be expressed as
Y= a + jb
Where,
Y = Admittance in siemens
a = Conductance in siemens \(= \frac{R}{{{R^2} + {X^2}}}\)
b = Susceptance in siemens \(= \frac{{ - X}}{{{R^2} + {X^2}}}\)
