# A magnetic circuit has a 20 cm lenght core with a permeability of 0.005 Wb/(Atm). The coil has 250 turns, and draws 0.4 ampere. Determine the mmf of the coil

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### 1 Answer

Magnetomotive force (mmf or simply F) is a measure of the strength of magnetic field in a coil. Conceptually it is analogous to electromotive force in a resistor circuit. For a given length of a coil, mmf can be increased by increasing the number of turns in the circuit.

The magnitude of magnetomotive force is obtained by multiplying the number of turns with the current strength.

F = N*I

Here, N = 250, I = 0.4 amperes

So, F= 250*0.4 = 100

Therefore, the mmf of the coil is 100 ampere-turns.

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