Related Questions

Which of the fpllowing inductor will have the least eddy current losses ?
A Air core
B Laminated iron core
C Iron core
D Powdered iron core
No eddy current and hysteresis losses occur in
A Electrostatic instruments
B PMMC instruments
C Moving iron instruments
D Electrodynamo meter instruments
A laminated iron core has reduced eddy-current losses because
A More wire can be used with less D.C. resistance in coil
B The laminations are insulated from each other
C The magnetic flux is concentrated in the air gap of the core
D The laminations are stacked vertically
An ohmmeter is connected across an inductor and the pointer indicates zero ohms. The inductor is
A Good
B Open
C Shorted
D Partly shorted
Which of the following is an advantage of eddy current heating?
A The amount of heat generated can be controlled accurately
B Heat at very high rate can be generated
C The area of the surface over which heat is produced can be accurately controlled
D All of the above
The disc of an instrument using eddy current damping should be of
A conducting and magnetic material
B non-conducting and magnetic material
C conducting and non-magnetic material
D none 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
Hysteresis loss and eddy current loss are used in
A Induction heating of steel
B Dielectric heating
C Induction heating of brass
D Resistance heating
Reducing the amount of current through an inductor:
A reduces the value of inductance by one-half
B multiplies the value of inductance by four
C multiplies the value of inductance by two
D has no effect on the inductance
E None of the above
A sine wave voltage is applied across an inductor. When the frequency of the voltage is decreased, the current
A Is increased
B Is decreased
C Does not change
D Momentarily goes to zero

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