Magnetic Circuit(Engineering > 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?
E.M.F.
Current
Current density
Conductivity
Explanation:-
Answer: Option B. -> Current
Question 2. Point out the wrong statement. Magnetic leakage is undesirable in electric machines because it
Lowers their power efficiency
Increases their cost of manufacture
Leads to their increased weight
Produces fringing
Explanation:-
Answer: Option A. -> Lowers their power efficiency
Question 3. The unit of magnetic flux is
Henry
Weber
Ampere-turn/weber
Ampere/metre
Explanation:-
Answer: Option B. -> Weber
Question 4. Those materials are well suited for making permanent magnets which have ________ retentivity and ________ coercivity.
Low, high
High, high
High, low
Low, low
Explanation:-
Answer: Option B. -> High, high
Question 5. Laminated cores, in electrical machines, are used to reduce
Copper loss
Eddy current loss
Hysteresis loss
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.
High, high
Low, high
High, low
Low, low
Explanation:-
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
50
20
0.05
500
Explanation:-
Answer: Option B. -> 20
Question 8. Relative permeability of vacuum is
1
1 H/m
1/4JI
4n × 10' H/m
Explanation:-
Answer: Option A. -> 1
Question 9. In a magnetic material hysteresis loss takes place primarily due to
Rapid reversals of its magnetization
Flux density lagging behind magnetizing force
Molecular friction
It high retentivity
Explanation:-
Answer: Option D. -> It high retentivity
Question 10. Permeability in a magnetic circuit corresponds to_________ in an electric circuit.