What is the usual value of leakage coefficient for electrical machines?
0.5 to 1
1 to 5
5 to 10
1.15 to 1.25
Correct Answer :
D. 1.15 to 1.25
Related Questions
The unit of flux density is
Wb/m
Tesla
At/m
N/Wb
What is the unit of magnetomotive force?
Volt
Tesla
Ampere- turn
Weber
The magnetic flux through a coil changes. This results to the induced emf acting in a direction as to
Oppose the change
Aid the change
Either oppose or aid the change
Neither oppose nor aid the change
The tiniest element of matter
Atom
Proton
Electron
Neutron
Materials whose permeabilities are slightly greater than that of free space
Paramagnetic
Non- magnetic
Ferromagnetic
Diamagnetic
A law establishing the fact that the algebraic su of the rises and drops of the mmf around a closed loop of a magnetic circuit is equal to zero.
Kirchhoff's circuital law
Maxwell's circuital law
Ampere's circuital law
Coulomb's circuital law
What is the SI unit of magnetic flux?
Tesla
Weber
Maxwell
Gauss
Materials that have very high permeabilities (hundreds and even thousands times of that of free space)
Paramagnetic
Non- magnetic
Ferromagnetic
Diamagnetic
Which of the following materials has permeability slightly less than that of free space?
Paramagnetic
Non- magnetic
Ferromagnetic
Diamagnetic
A substance that attracts pieces iron
Conductor
Semiconductor
Magnet
All of the above
A 200-watt lamp working for 24 hours will consume approximately _____ units.
What is the practical unit of electrical energy?
Watt
Kilowatt-hour
Kilowatt-second
Megawathour
As the magnetic intensity decreasesa the relative permeability of a magnetic material
decreases
remains the same
increases
becomes zero
It is the reciprocal of reluctance and implies the case of readiness with which magnetic flux is developed.
R esistance
Conductance
Permeance
I nductance
When the relative permeability of a material is slightly less than 1a it is called _____ material.
diamagnetic
ferromagnetic
paramagnetic
non-magnetic
Theory of ferromagnetic phenomena which assumes each atom is a permanent magnet which can turn freely about its center under the influence of applied field and other magnets.
Ewing's theory of ferromagnetism
Oersted's ferromagnetism theory
Maxwell's magnetic theory
Ampere's circuital law
The conduction of electricity across the surface of a dielectric is called
creepage
skin effect
surface effect
crosstalk
The current of electric circuit is analogous to which quantity of a m
Mmf
Flux
Flux density
R eluctivity
Calculate the flux density that will be produced by the field intensity of 2000 a. t/m for a permeability of 126 x 10^-6 T/A.t/m
0.252 G
0.252 x 10^-2 T
0.252 T
0.252 x 10^-2 G
Ohm's law can be used only to a _____ circuit or component.
Unilateral
Exponential
Trivalent
Linear
The hot resistance of an incandescent lamp is about _______ its cold resistance.
10 times
100 times
5 times
50 times
A law stating that the magnetic susceptibilities of most paramagnetic substances are inversely proportional to their absolute temperatures.
Curie's Law
Child's Law
CR Law
Curie-Weiss Law
A law that states that the polarity of the induced voltage will oppose the change in magnetic flux causing the induction.
Joule's law
Faraday's law
Coulomb's law
Lenz' law
The unit of electrical energy is
Joule
Watt- second
Kilowatt hour
All of these
When the relative permeability of a material is much greater than 1a it is called _______ material.
diamagnetic
ferromagnetic
paramagnetic
non-magnetic
The direction of force o a current carrying conductor placed in a m found by
Cork screw rule
Fleming's left hand rule
Fleming's right hand rule
using a compass
The reluctance of a magnetic circuit is not dependent on which of the following?
Number of turns of coil
Magnetomotive force
Flux density in the circuit
Current in the coil
If the length and area of cross-section of a wire are doubleda then its resistance
becomes four times
becomes sixteen times
remains the same
becomes two times
The induced emf in a wire loop that is moved parallel to a uniform magnetic field is
Zero
Dependent on the area of the loop
Dependent on the shape of the loop
Dependent on the magnitude of the field
Who discovered the most important electrical effects which is the magnetic effect?
Hans Christian Oersted
Sir Charles Wheatstone
Georg Ohm
James Clerk Maxwell