## Multiple Choice Questions(MCQ) on Magnetic Circuit for Electrical Engineering

1. An air gap is usually inserted in magnetic circuits to
(a) increase m.m.f.
(b) increase the flux
(c) prevent saturation
(d) none of the above

Ans: c

2. Energy stored by a coil is doubled when its current is increased by percent.
(a) 25
(b) 50
(c)41.4
(d) 100

Ans: c

3. The rate of rise of current through an inductive coil is maximum
(a) at 63.2% of its maximum steady value
(b) at the start of the current flow
(c) after one time constant
(d) near the final maximum value of current

Ans: b

4. In a magnetic material hysteresis loss takes place primarily due to
(a) rapid reversals of its magnetization
(b) flux density lagging behind magnetizing force
(c) molecular friction
(d) it high retentivity

Ans: d

5. The unit of retentivity is
(a) weber
(b) weber/sq. m
(c) ampere turn/meter
(d) ampere turn

Ans: b

6. Reciprocal of reluctance is
(a) reluctivity
(b) permeance
(c) permeability
(d) susceptibility

Ans: b

7. 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

Ans: a

8. Hysteresis loss least depends on
(a) volume of material
(b) frequency
(c) steinmetz coefficient of material
(d) ambient temperature

Ans: d

9. Laminated cores, in electrical machines, are used to reduce
(a) copper loss
(b) eddy current loss
(c) hysteresis loss
(d) all of the above

Ans: b

10. While comparing magnetic and electric circuits, the flux of magnetic circuit is compared with which parameter of electrical circuit ?
(a) E.m.f.
(b) Current
(c) Current density
(d) Conductivity

Ans: b

Tags-
#MCQ on electrical engineering
#Magnetic Circuit mcq.
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