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Unit of MMF is ______________
A/m
m
unitless
The Magnetomotive Force (MMF) is defined as the magnetic analogue of electromotive force (EMF) in electric circuits. Its SI unit is the Ampere-turn (AT), which is often simplified to just Ampere (A) since 'turn' is a dimensionless quantity.
The Magnetomotive Force (MMF) is defined as the magnetic analogue of electromotive force (EMF) in electric circuits. Its SI unit is the Ampere-turn (AT), which is often simplified to just Ampere (A) since 'turn' is a dimensionless quantity.
F=NI тАФ where F is MMF in Ampere-turns, N is the number of turns, and I is the current in Amperes
F=╬жRmтАЛ тАФ where ╬ж is magnetic flux and RmтАЛ is reluctance
MMF is the driving force that establishes magnetic flux in a magnetic circuit. It is proportional to the number of turns in a coil and the current flowing through it, mathematically represented as F=NI. As current is measured in Amperes and the number of turns is a scalar count, the resulting unit is the Ampere.
MMF is measured in Ampere-turns (AT) in the SI system.
It acts as the magnetic potential difference across a magnetic circuit.
The 'turn' component is dimensionless, hence the unit is fundamentally the Ampere.
Provides a simple analogy to Ohm's Law for magnetic circuits (F=╬жRmтАЛ)
Easily quantifiable by measuring coil current and counting windings
Depends on core saturation which makes the magnetic resistance (reluctance) non-linear
Leakage flux can cause inaccuracies in theoretical calculations
Transformers
Electric motors and generators
Electromagnets and solenoids
While the CGS unit for MMF is the Gilbert, the SI unit is the Ampere-turn.
Option A (A/m) is the unit of Magnetic Field Intensity (H).
Option B (m) is a unit of length.
Option D (unitless) is incorrect as MMF has a physical dimension.
C is correct тАФ The unit of Magnetomotive Force (MMF) is Ampere (or Ampere-turn).
Always distinguish between MMF (F=NI) and Magnetic Field Intensity (H=NI/l). MMF has units of Amperes, while H has units of Amperes per meter.