Q.106____ is defined as the property which is responsible for the induced emf in one coil due to change in current flowing through some other coil placed nearby it.
A. Coefficient of coupling
B. Magnetic coupling coefficient
C. mutual inductance
D. all of the above
Ans.: D
Q.107 The coefficient of coupling is measured in___.
A. Henry
B. Henry/meter
C. meter/Henry
Ans.: A
Q.108 mathematical expression for coefficient of coupling is:
A. K = M/ L1 L2
B. K = L1 L2
C. K = M/ √L1 L2
D. K = L1L2/M
Ans.: C
Q.109 Maximum value of K is
A. less than 1
B. 1
C. more than 1
D. any of the above
Ans.: B
Q.110 If the value of K = 1, then the value of mutual inductance will be__.
A. minimum
B. zero
C. maximum
D. infinite
Ans.: C
Q.111 If the instantaneous flux produced by two coils always add with each other then this two coils are___.
A. series aiding
B. cumulatively coupling
C. series opposition
D. Both A and B
Ans.: D
Q.112 The correct equation of the deferentially connected coils is__
A. Leq = L1 – L2 + 2M
B. Leq = L1 + L2 – 2M
C. Leq = L1 – L2 -2M
D. Leq = L1 + L2 + 2M
Ans.: B
Q. 113 Two series connected coils are said to be in series opposition or connected deferentially if their instantaneous fluxes are in__
A. same direction to each other
B. opposite direction to each other
C. opposite to that of supply
D. none of the above
Ans.: B
Q.114 which of the following is correct equation for series aiding or cumulatively coupling?
A. Leq = L1 + L2 + 2M
B. Leq = L1 – L2 -2M
C. Leq = L1 – L2 + 2M
D. Leq = L1 + L2 – 2M
Ans.: A
Q.115 The energy stored in a magnetic circuit is _____ to the value of self inductance L and to the ____ of the current flowing through the coil.
A. inversely proportional, square
B. directly proportional, square
C. directly proportional, three times
D. directly proportional, half
Ans.: B
Q.116 Due to induced emf a circulating current is produced in the iron core, which are called as ___.
A. hysteresis loss
B. eddy current loss
C. eddy current
D. power less
Ans.: C
Q.116 what are the effect of eddy current?
A. power loss
B. produce heat
C. energy loss
D. all of the above
Ans.: D
Q.117 how to reduce eddy current?
A. core is made up from insulated, thin, iron sheets called laminations
B. core is made of solid iron, thick
C. lamination is not required
D. all of the above
Ans.: A
Q.118 What are the factors affecting the eddy current loss?
A. Thickness of the laminations
B. Frequency and maximum flux density
C. volume of the magnetic materials
D. all of the above
Ans.: D
Q.119 Thicker the lamination____
A. lower is the eddy current
B. higher is the eddy current
C. eddy current does not depend upon laminations
D. none of the above
Ans.: B
Q.120 The eddy current loss increase with increase in frequency because it is____.
A. proportional to frequency
B. proportional to the cube of frequency
C. proportional to the square of frequency
D. inversely proportional to the frequency
Ans.: C