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MCQs

Total Questions : 112 | Page 1 of 12 pages
Question 1. While comparing magnetic and electric circuits, the flux of magnetic circuit is compared with which parameter of electrical circuit?
  1.    E.M.F.
  2.    Current
  3.    Current density
  4.    Conductivity
 Discuss Question
Answer: Option B. -> Current
Question 2. Point out the wrong statement. Magnetic leakage is undesirable in electric machines because it
  1.    Lowers their power efficiency
  2.    Increases their cost of manufacture
  3.    Leads to their increased weight
  4.    Produces fringing
 Discuss Question
Answer: Option A. -> Lowers their power efficiency
Question 3. The unit of magnetic flux is
  1.    Henry
  2.    Weber
  3.    Ampere-turn/weber
  4.    Ampere/metre
 Discuss Question
Answer: Option B. -> Weber
Question 4. Those materials are well suited for making permanent magnets which have ________ retentivity and ________ coercivity.
  1.    Low, high
  2.    High, high
  3.    High, low
  4.    Low, low
 Discuss Question
Answer: Option B. -> High, high
Question 5. Laminated cores, in electrical machines, are used to reduce
  1.    Copper loss
  2.    Eddy current loss
  3.    Hysteresis loss
  4.    All of the above
 Discuss Question
Answer: Option B. -> Eddy current loss
Question 6. Those magnetic materials are best suited for making armature and transformer cores which have ________permeability and _________hysteresis loss.
  1.    High, high
  2.    Low, high
  3.    High, low
  4.    Low, low
 Discuss Question
Answer: Option C. -> High, low
Question 7. The initial rate of rise of current through a coil of inductance 10 H when suddenly connected to a D.C. supply of 200 V is ___________Vs
  1.    50
  2.    20
  3.    0.05
  4.    500
 Discuss Question
Answer: Option B. -> 20
Question 8. Relative permeability of vacuum is
  1.    1
  2.    1 H/m
  3.    1/4JI
  4.    4n × 10' H/m
 Discuss Question
Answer: Option A. -> 1
Question 9. In a magnetic material hysteresis loss takes place primarily due to
  1.    Rapid reversals of its magnetization
  2.    Flux density lagging behind magnetizing force
  3.    Molecular friction
  4.    It high retentivity
 Discuss Question
Answer: Option D. -> It high retentivity
Question 10. Permeability in a magnetic circuit corresponds to_________ in an electric circuit.
  1.    Resistance
  2.    Resistivity
  3.    Conductivity
  4.    Conductance
 Discuss Question
Answer: Option C. -> Conductivity

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