Electromagnetics Field (3140912) MCQs

MCQs of Magnetic forces, materials and inductance

Showing 111 to 120 out of 171 Questions
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111.
Ferrite core has less eddy current loss than an iron core because
(a) They have high resistance
(b) They are magnetic
(c) They have low permeability
(d) They have high hysteresis
Answer:

Option (a)

112.
Hysteresis loss least depends on
(a) Volume of material
(b) Frequency
(c) Steinmetz co-efficient of material
(d) Ambient temperature
Answer:

Option (d)

113.
Laminated cores, in electrical machines are used to reduce
(a) Copper loss
(b) Eddy current loss
(c) Hysteresis loss
(d) All of above
Answer:

Option (b)

114.
The property of coil by which a counter emf is induced in it when the current through the coil changes is known as
(a) Self-inductance
(b) Mutual inductance
(c) Capacitance
(d) None of above
Answer:

Option (a)

115.
As per Faraday's laws of electromagnetic induction, an emf is induced in a conductor whenever it
(a) Lies perpendicular to the magnetic flux
(b) Lies in a magnetic field
(c) Cuts magnetic flux
(d) Moves parallel to the direction of the magnetic field
Answer:

Option (c)

116.
Which of the following circuit element stores energy in the electromagnetic field ?
(a) Inductance
(b) Condenser
(c) Resistance
(d) None of above
Answer:

Option (a)

117.
The inductance of a coil will increase under all the following conditions except
(a) When more length for the same number of turns is provided
(b) When the number of turns of the coil increase
(c) When more area for each turn is provided
(d) When permeability of the core increases
Answer:

Option (a)

118.
Higher the self-inductance of a coil,
(a) Lesser is its weber-turns
(b) Lower the emf induced
(c) Greater the flux produced
(d) Delay in establishing steady current through it
Answer:

Option (d)

119.
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 same
(d) Initially increase and then decrease
Answer:

Option (b)

120.
An open coil has
(a) Zero resistance and inductance
(b) Infinite resistance and zero inductance
(c) Infinite resistance and normal inductance
(d) Zero resistance and high inductance
Answer:

Option (b)

Showing 111 to 120 out of 171 Questions
9 10 11 12 13 14