Top 350+ Solved Electromagnetics MCQ Questions Answer
Q. Hard steel is suitable for making permanent magnets because
a. it has good residual magnetism
b. its hysteresis loop has large area
c. its mechanical strength is high
d. its mechanical strength is low
Q. Silicon steel is used in electrical machines because it has
a. low co-ercivity
b. low retentivity
c. low hysteresis loss
d. high co-ercivity
Q. The property of a material which opposes the creation of magnetic flux in it is known as
a. reluctivity
b. magnetomotive force
c. permeance
d. reluctance
Q. A ferrite core has less eddy current loss than an iron core because
a. ferrites have high resistance
b. ferrites are magnetic
c. ferrites have low permeability
d. ferrites have high hysteresis
Q. Hysteresis loss least depends on
a. volume of material
b. frequency
c. steinmetz co-efficient of material
d. ambient temperature
Q. Laminated cores, in electrical machines, are used to reduce
a. copper loss
b. eddy current loss
c. hysteresis loss
d. all of the above
Q. The property of coil by which a counter e.m.f. is induced in it when the current throughthe coil changes is known as
a. self-inductance
b. mutual inductance
c. series aiding inductance
d. capacitance
Q. Which of the following circuit element stores energy in the electromagnetic field ?
a. inductance
b. condenser
c. variable resistor
d. resistance
Q. Higher the self-inductance of a coil,
a. lesser its weber-turns
b. lower the e.m.f. induced
c. greater the flux produced by it
d. longer the delay in establishing steady current through it
Q. In an iron cored coil the iron core is removed so that the coil becomes an air cored coil.The inductance of the coil will
a. increase
b. decrease
c. remain the same
d. initially increase and then decrease
Q. Both the number of turns and the core length of an inductive coil are doubled.Its self-inductance will be
a. unaffected
b. doubled
c. halved
d. quadrupled