1) The B-H curve for __________ will be a straight line passing through the origin
a) air
b) soft iron
c) hardened steel
d) silicon steel
2) For 1 m3 of material, the hysteresis loss will be minimum for
a) soft iron
b) steel
c) cobalt steel
d) silicon steel
3) The SI unit reluctance is
a) AT/Wb
b) AT/m
c) AT
d) N/Wb
su_spoiler title=”View Answer” style=”fancy” icon=”arrow-circle-1″]Option – a)[/su_spoile]
4) The value of leakage co-efficient for electrical machines is usually about…….
a) 0.5 to 1
b) 4 to 10
c) above 10
d) 1.15 to 1.25
5) The unit of relative permeability is
a) AT/m
b) N/Wb
c) AT/m2
d) a number
6) At high frequencies the material used for transformer cores is
a) silicon iron
b) soft iron
c) ferrite
d) none of the above
7) Out of the following materials, the area of hysteresis loop will be least for………
a) wrought iron
b) hard steel
c) silicon steel
d) soft steel
8) The magnetic material used for ……… should have a large hysteresis loop.
a) transformers
b) d.c generators
c) a.c motors
d) permanent magnets
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9) The B-H curve of a ferromagnetic material is
a) linear
b) non-linear
c) circle
d) none of the above
10) The material used for the core of a good relay should have ……… hysteresis loop.
a) large
b) very large
c) narrow
d) none of the above