# 300+ TOP Magnetic Circuit MCQ Questions and Answers

## MAGNETIC CIRCUIT Multiple Choice Questions with Answers :-

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

2. The relative permeability of a ferromagnetic material is
A. less than one
B. more than one
C. more than 10
D. more than 100 or 1000

3. The unit of magnetic flux is
A. henry
B. weber
C. ampereturn/weber
D. ampere/metre

4. Permeability in a magnetic circuit corresponds to______ in an electric circuit.
A. resistance
B. resistivity
C. conductivity
D. conductance

5. Point out the wrong statement.
Magnetic leakage is undesirable in electric machines because it
A. lowers their power efficiency
B. increases their cost of manufacture
C. leads to their increased weight
D. produces fringing

6. Relative permeability of vacuum is
A. 1
B. 1 H/m
C. 1/4JI
D. 4n x 10-‘ H/m

7. Permanent magnets are normally made of
A. alnico alloys
B. aluminium
C. cast iron
D. wrought iron

8. Energy stored by a coil is doubled when its current is increased by percent.
A. 25
B. 50
C.41.4
D. 100

9. Those magnetic materials are best suited for making armature and transformer cores which have____permeability and_______hystersis loss.
A. high, high
B. low, high
C. high, low
D. low, low

10. 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

11. When both the inductance and resistance of a coil are doubled the value of
A. time constant remains unchanged
B. initial rate of rise of current is doubled
C. final steady current is doubled
D. time constant is halved

12. The initial rate of rise of current through a coil of inductance 10 H when suddenly connected to a D.C. supply of 200 V is_______Vs
A. 50
B. 20
C. 0.05
D. 500

13. A material for good magnetic memory should have
A. low hysteresis loss
B. high permeability
C. low retentivity
D. high retentivity

14. Conductivity is analogous to
A. retentivity
B. resistivity
C. permeability
D. inductance

15. In a magnetic material hysteresis loss takes place primarily due to
A. rapid reversals of its magnetisation
B. flux density lagging behind magnetising force
C. molecular friction
D. it high retentivity

16. Those materials are well suited for making permanent magnets which have _____ retentivity and _______ coercivity.
A. low, high
B. high, high
C. high, low
D. low, low

17. If the area of hysteresis loop of a material is large, the hysteresis loss in this material will be
A. zero
B. small
C. large
D. none of the above

18. 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

19. Silicon steel is used in electrical machines because it has
A. low coercivity
B. low retentivity
C. low hysteresis loss
D. high coercivity

20. Conductance is analogous to
A. permeance
B. reluctance
C. flux
D. inductance

21. 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

22. The unit of retentivity is
A. weber
B. weber/sq. m
C. ampere turn/meter
D. ampere turn

23. Reciprocal of reluctance is
A. reluctivity
B. permeance
C. permeability
D. susceptibility

24. 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

25. The unit of reluctance is
A. metre/henry
B. henry/metre
C. henry
D. 1/henry

26. 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

27. Hysteresis loss least depends on
A. volume of material
B. frequency
C. steinmetz coefficient of material
D. ambient temperature

28. Laminated cores, in electrical machines, are used to reduce
A. copper loss
B. eddy current loss
C. hysteresis loss
D. all of the above

### MAGNETIC CIRCUIT objective questions with answers pdf download online exam test

#### 7 thoughts on “300+ TOP Magnetic Circuit MCQ Questions and Answers”

1. sushmitha j says:

sir i have applied for kpcl exam 2017 for electrical je post plz provide objective types question based on that syllabus

2. B G SHENDGE says:

Please send me quastion answers on ELECTRICAL ENGINEERING in pdf please

3. Beereshekkelore says:

Question no 25 is how

4. arun says:

i m sorry i was wrong ….answer should be D

5. arun says:

answer of q no 27 will be B

6. sarita says:

How???? I think optin D for Ques 26.

7. Dibakar mech says:

Sir, can you provide objective question on alternator in pdf file.