Chapter 1 - Magnetic Circuit

Which of the following represents the correct formula for magnetomotive force (MMF)?

• MMF=N/I

• MMF=I/N

• MMF=N×I

• MMF=N/R

What does a high value of permeability (μ) indicate in a magnetic material?

• High reluctance

• Low magnetic flux

• Good conductor of magnetic flux

• High resistance

Which law explains the induced electromotive force (EMF) in a coil due to a changing magnetic flux?

• Ampere’s Law

• Lenz's Law

• Ohm’s Law

• Faraday’s Law of Electromagnetic Induction

What type of material is best suited for use in transformer cores due to its high permeability and low hysteresis loss?

• Plastic

• Wood

• Copper

• Silicon steel

Which quantity is defined as the property of a coil that opposes any change in the current flowing through it?

• Inductance

• Conductance

• Resistance

• Capacitance

Which of the following is NOT a ferromagnetic material?

• Iron

• Aluminium

• Cobalt

• Nickel

Faraday’s Law states that the induced EMF in a coil is directly proportional to:

• The resistance of the coil

• The number of turns and rate of change of magnetic flux

• The inductance of the coil

• The current flowing in the coil

How can eddy current loss be minimized in magnetic cores?

• Increasing voltage

• Using laminated cores

• Increasing core thickness

• Using ferromagnetic oil

Which type of energy loss in a magnetic material is caused by repeated magnetization and demagnetization?

• Eddy current loss

• Copper loss

• Hysteresis loss

• Mechanical loss

Which factor does NOT directly affect eddy current loss in a magnetic core?

• Frequency of magnetization

• Thickness of core material

• Magnetic field strength

• Wire insulation resistance