Question 1
Question
A natural magnet is called
Answer
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steel
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lodestone
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magnetism
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soft iron
Question 2
Question
A magnet is able to attract
Answer
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iron, aluminum and brass
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iron, cobalt and zinc
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iron, copper and nickel
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nickel, cobalt and steel
Question 3
Question
Externally, magnetic line of force travels
Answer
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south to north
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north to south
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negative to positive
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in both directions
Question 4
Question
A material commonly used for shielding or screening magnetism is
Answer
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brass
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aluminum
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copper
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soft iron
Question 5
Question
The magnetism that remains in a magnet after the magnetizing force has been removed is called
Answer
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permeability
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induction
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residual
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saturation
Question 6
Question
Iron becomes magnetized by induction when it is
Question 7
Question
Magnetic lines of force are called
Answer
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hysteresis
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current
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flux
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magnetomotive force
Question 8
Question
The force between two magnetic poles varies with distance between them. The variation is
Answer
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in direct proportion to the distance
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in inverse proportion to the distance
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in direct proportion to the square of the distance
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in inverse proportion to the square of the distance
Question 9
Question
The magnetic potential in a magnetic circuit can be measured in terms of
Answer
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farads
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M.M.F.
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coulombs
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none of these
Question 10
Question
Permeance is analogous to
Answer
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conductance
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resistance
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reluctance
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none of these
Question 11
Question
The permeability of a material means
Answer
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strength of permanent magnet
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strength of an electromagnet
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the magnetization left in the iron after exciting field has been removed
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the conductivity of a material for magnetic lines of force
Question 12
Question
When magnetic flux (Φ) and the area (A) under its influence are known, the magnetic flux density (B) can be given as
Answer
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B = ΦA
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B = Φ/A
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B = A/Φ
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B = ΦA2
Question 13
Question
The relative permeability μr is given by
Question 14
Question
Relative permeability of a material is given by (K is susceptibility of the material)
Answer
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1 + μ0K
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1 + K/μ0
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1 + μ0/K
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μ0H
Question 15
Question
The relative permeability of paramagnetic substance is
Answer
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slightly less than 1
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equal to 1
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slightly greater than 1
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very much greater than 1
Question 16
Question
The value of permeability for the free space is
Answer
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4 x 10^-7 Hm-1
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4π x 10^-7 Hm-1
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4π x 10^7 Hm-1
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1/4π x 10^-7 Hm-1
Question 17
Question
The magnetization in any magnetic material appears as a result of
Question 18
Question
The sum of the magnetic moments in unit volume of the solid is called
Answer
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field strength
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magnetism
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permeability
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susceptibility
Question 19
Question
Which of the following materials does not have permanent magnetic dipole
Answer
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paramagnetic
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antiferromagnetic
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diamagnetic
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ferrimagnetic
Question 20
Question
Interaction between the neighboring dipoles is negligible in case of a
Question 21
Question
Each ferromagnetic material has characteristic temperature above which its properties are quite different from those below that temperature. That temperature is called
Question 22
Question
The relative permability μ for iron is
Question 23
Question
Which of the following material is used for making permanent magnets
Answer
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carbon steel
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platinum cobalt
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Alnico V
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All of these
Question 24
Question
Which of the following has the highest value of relative permeability
Answer
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iron
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supermalloy
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Mu-metal
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4% Si - Fe
Question 25
Question
Ferrimagnetic materials generally behave as a
Answer
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semiconductor
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conductor
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insulator
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any of A, B, or C
Question 26
Question
Transformer cores operating at microwave frequency ranges are generally made up of
Answer
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ferrites
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silicon steel
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supermalloy
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alnico V
Question 27
Question
The magnetic materials which can be easily magnetized in both directions are known as
Question 28
Question
Eddy current loss can be minimized by
Answer
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decreasing the resistance of magnetic medium
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increasing the resistance of magnetic medium
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decreasing the permeability of magnetic medium
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none of these