Electromagnetics Field (3140912) MCQs

MCQs of Magnetic forces, materials and inductance

Showing 21 to 30 out of 171 Questions
1 2 3 4 5 6
21.
Materials subjected to rapid reversal of magnetism should have
(a) Large area of hysteresis loop
(b) High permeability and low hysteresis loss
(c) High coercivity and high retentivity
(d) High coercivity and low retentivity
Answer:

Option (b)

22.
Which material does not retain magnetism permanently?
(a) Soft iron
(b) Stainless steel
(c) Hardened steel
(d) None of above
Answer:

Option (a)

23.
The main constituent of permalloy is
(a) Cobalt
(b) Chromium
(c) Nickel
(d) Tungsten
Answer:

Option (c)

24.
Permanent magnets is not used in
(a) Magnetoes
(b) Energy meters
(c) Transformers
(d) Loud-speakers
Answer:

Option (c)

25.
Paramagnetic materials have relative permeability
(a) Slightly less than unity
(b) Equal to unity
(c) Slightly more than unity
(d) Equal to that ferromagnetic materials
Answer:

Option (c)

26.
Degaussing is the process of
(a) Removal of magnetic impurities
(b) Removal of gases from the materials
(c) Remagnetizing metallic parts
(d) Demagnetizing metallic parts
Answer:

Option (d)

27.
Substances which have permeability less than the permeability of free space are known as
(a) Ferromagnetic
(b) Paramagnetic
(c) Diamagnetic
(d) Bipolar
Answer:

Option (c)

28.
In Fleming's left hand rule, forefinger always represents
(a) Voltage
(b) Current
(c) Magnetic field
(d) Direction of force on the conductor
Answer:

Option (c)

29.
Which is the ferromagnetic material ?
(a) Tungsten
(b) Aluminum
(c) Copper
(d) Nickel
Answer:

Option (d)

30.
Ferrites are subgroup of
(a) Nonmagnetic materials
(b) Ferromagnetic materials
(c) Paramagnetic materials
(d) Ferrimagnetic materials
Answer:

Option (d)

Showing 21 to 30 out of 171 Questions
1 2 3 4 5 6