Chapter 3, Problem 3.1MCQ

The “Ohm’s law” for the magnetic circuit states that the net magnetomotive force (mmf) equals the product of the core reluctance and the core flux.

(a) True

(b) False

To determine

Whether the given statement is true or false.

Answer to Problem 3.1MCQ

The given statement is true. The correct option is (a).

Explanation of Solution

Magneto-motive force is analogous to electro-motive force, magnetic flux is analogous to electric current and magnetic reluctance is analogous to electric resistance.

So ohm law for magnetic circuit can be stated as "magnetic flux produced in magnetic circuit is directly proportional to magneto-motive force".

Therefore, $\varphi \text{α}F$

Simplify above equation.

  $\varphi =\frac{F}{R_l}$

Rearrange above equation.

  $F=\varphi R_l$

Here, $F$ is magneto-motive force, $\varphi$ is magnetic flux and $R_l$ is value of reluctance.

So net magneto-motive force equal the product of core reluctance and core flux.

Thus, the given statement is true. The correct option is (a).