20634399
Descrição
Quiz por Owen Ryan Ang, atualizado more than 1 year ago
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Criado por Owen Ryan Ang
mais de 4 anos atrás
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|
Questão 1
Questão
A natural magnet is called
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steel
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lodestone
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magnetism
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soft iron
Questão 2
Questão
A magnet is able to attract
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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
Questão 3
Questão
Externally, magnetic line of force travels
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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
Questão 4
Questão
A material commonly used for shielding or screening magnetism is
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brass
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aluminum
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copper
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soft iron
Questão 5
Questão
The magnetism that remains in a magnet after the magnetizing force has been removed is called
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permeability
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induction
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residual
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saturation
Questão 6
Questão
Iron becomes magnetized by induction when it is
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heated
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suspended east and west
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near to one end of a magnet
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treated with some chemicals
Questão 7
Questão
Magnetic lines of force are called
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hysteresis
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current
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flux
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magnetomotive force
Questão 8
Questão
The force between two magnetic poles varies with distance between them. The variation is
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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
Questão 9
Questão
The magnetic potential in a magnetic circuit can be measured in terms of
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farads
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M.M.F.
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coulombs
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none of these
Questão 10
Questão
Permeance is analogous to
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conductance
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resistance
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reluctance
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none of these
Questão 11
Questão
The permeability of a material means
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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
Questão 12
Questão
When magnetic flux (Φ) and the area (A) under its influence are known, the magnetic flux density (B) can be given as
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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
Questão 13
Questão
The relative permeability μr is given by
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B/μr0H
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B/H
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μ0/μ
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μ0/H
Questão 14
Questão
Relative permeability of a material is given by (K is susceptibility of the material)
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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
Questão 15
Questão
The relative permeability of paramagnetic substance is
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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
Questão 16
Questão
The value of permeability for the free space is
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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
Questão 17
Questão
The magnetization in any magnetic material appears as a result of
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electrons orbital motion
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electron spin
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spin of the nucleus about its axis
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all of these
Questão 18
Questão
The sum of the magnetic moments in unit volume of the solid is called
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field strength
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magnetism
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permeability
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susceptibility
Questão 19
Questão
Which of the following materials does not have permanent magnetic dipole
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paramagnetic
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antiferromagnetic
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diamagnetic
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ferrimagnetic
Questão 20
Questão
Interaction between the neighboring dipoles is negligible in case of a
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paramagnetic material
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diamagnetic material
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antiferromagnetic material
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ferrimagnetic material
Questão 21
Questão
Each ferromagnetic material has characteristic temperature above which its properties are quite different from those below that temperature. That temperature is called
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transition temperature
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Faraday's temperature
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demagnetization temperature
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Curie' temperature
Questão 22
Questão
The relative permability μ for iron is
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5000
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7000
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3000
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1000
Questão 23
Questão
Which of the following material is used for making permanent magnets
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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
Questão 24
Questão
Which of the following has the highest value of relative permeability
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iron
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supermalloy
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Mu-metal
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4% Si - Fe
Questão 25
Questão
Ferrimagnetic materials generally behave as a
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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
Questão 26
Questão
Transformer cores operating at microwave frequency ranges are generally made up of
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ferrites
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silicon steel
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supermalloy
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alnico V
Questão 27
Questão
The magnetic materials which can be easily magnetized in both directions are known as
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soft magnetic materials
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hard magnetic materials
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low hysteresis loss materials
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high hysteresis loss materials
Questão 28
Questão
Eddy current loss can be minimized by
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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
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