Magnetic Circuit(Electrical Engineering ) Questions and Answers

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
Explanation:-
Answer: Option B. -> Current
Question 2. 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
Explanation:-
Answer: Option B. -> High, high
Question 3. 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
Explanation:-
Answer: Option A. -> Lowers their power efficiency
Question 4. The unit of magnetic flux is
  1.    Henry
  2.    Weber
  3.    Ampere-turn/weber
  4.    Ampere/metre
Explanation:-
Answer: Option B. -> Weber
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
Explanation:-
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
Explanation:-
Answer: Option C. -> High, low
Question 7. 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
Explanation:-
Answer: Option D. -> It high retentivity
Question 8. Relative permeability of vacuum is
  1.    1
  2.    1 H/m
  3.    $$4\pi \times {10^{ - 7}}$$
  4.    $$\frac{1}{4}$$
Explanation:-
Answer: Option A. -> 1
Question 9. Permeability in a magnetic circuit corresponds to_________ in an electric circuit.
  1.    Resistance
  2.    Resistivity
  3.    Conductivity
  4.    Conductance
Explanation:-
Answer: Option C. -> Conductivity
Question 10. 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
Explanation:-
Answer: Option B. -> 20
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