Q.121 The eddy current loss is directly proportional to the ____ of the material.
A. area
B. volume
C. thickness
D. laminations
Ans.: B
Q.122 Eddy current loss is directly proportional to the ___ of maximum flux density.
A. half
B. three times
C. square
D. four times
Ans.: C
Q.123 The total power loss taking place in a core due to _____ is called as the core loss or iron loss.
A. Eddy loss
B. hysteresis loss
C. Both A and B
D. copper loss
Ans.: C
Q.124 Core loss or iron loss is also called ___.
A. variable loss
B. constant loss
C. friction loss
D. stray loss
Ans.: B
Q.125 what are the effect of core loss or iron loss?
A. reduced the efficiency of a magnetic circuit
B. produces an undesirable heat
C. Both A and B
D. reduce life of magnetic circuit
Ans.: C
Q.126 which of the followings measures are to be taken to reduce the core loss?
A. use magnetic materials having narrow hysteresis loop
B. use materials such as silicon steel
C. use laminated cores
D. all of the above
Ans.: D
Q.127 How to reduce the iron loss?
A. reduce the working flux density
B. use material having low hysteresis coefficient
C. operate magnetic circuit at low frequency
D. all of the above
Ans.: D
Q.128 A conductor carries 10 A in a direction perpendicular to a magnetic field of density 0.3T, f length of conductor is 10 cm the force on the conductor F___.
A. 30 N
B. 0.3 N
C. 10 N
D. 0.5 N
Ans.: C
Q.129 A magnetic circuit has mean length of 20 cm and cross sectional area of 1cm2 if the flux density is 2T then value of ф is __.
A. 2 x 10-4Wb
B. 2 x 10-4mWb
C. 2 x 10-4µWb
D. 2 x 10-8Wb
Ans.: A
Q.130 Out of the following is a vector quantity.
A. flux density
B. magnetic field intensity
C. relative permittivity
D. current density
Ans.: B
Q.131 A current of 100 A flowing through the wire of 2.5m long is bent into a square will produce a magnetizing force at the centre of the square is equal to ___.
A. 144AT/m
B. 75AT/m
C. 175AT/m
D. 44AT/m
Ans.: B
Q.132 The coefficient of coupling of two air core coils is depends upon___.
A. mutual inductance and self inductance of the two coils
B. only mutual inductance of two coils
C. only self inductance of two coils
D. any of the above
Ans.: A
Q.133 The flux of magnetic circuit is compared with which parameter of electric circuit?
A. EMF
B. Current
C. Current density
D. electric field
Ans.: B
Q.134 The point of dissimilarity exists while comparing magnetic and electric circuit.
A. reluctance and resistance
B. MMF and EMF
C. Permeance and conductance
D. flux and current flow
Ans.: D
Q.135 which of the following circuit element will oppse the change in circuit current?
A. Inductance
B. Capacitance
C. resistance
D. Both A and B
Ans.: D
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