Computer Programming MCQs

5739 MCQs  (Page 172 of 574)

When both the inductance and resistance of a coil are doubled the value of________________?
A. Time constant remains unchanged
B. Initial rate of rise of current is doubled
C. Final steady current is doubled
D. Time constant is halved
Conductivity is analogous to____________?
A. Retentivity
B. Resistivity
C. Permeability
D. Inductance
Hard steel is suitable for making permanent magnets because_____________?
A. It has good residual magnetism
B. Its hysteresis loop has large area
C. Its mechanical strength is high
D. Its mechanical strength is low
Conductance is analogous to_____________?
A. Permeance
B. Reluctance
C. Flux
D. Inductance
The unit of retentivity is____________?
A. Weber
B. Weber/sq. m
C. Ampere turn/meter
D. Ampere turn
Laminated cores, in electrical machines, are used to reduce____________?
A. Copper loss
B. Eddy current loss
C. Hysteresis loss
D. All of the above
A ferrite core has less eddy current loss than an iron core because_______________?
A. Ferrites have high resistance
B. Ferrites are magnetic
C. Ferrites have low permeability
D. Ferrites have high hysteresis
Silicon steel is used in electrical machines because it has_____________?
A. Low coercivity
B. Low retentivity
C. Low hysteresis loss
D. High coercivity