What is the practical unit of electrical energy?
Watt
Kilowatt-hour
Kilowatt-second
Megawathour
Correct Answer :
B. Kilowatt-hour
Related Questions
Two similar polesa each 1Wba placed 1 m apart in air will experience a repulsive force of
63000 N
63 × 10^-3 N
8 × 10^12 N
796 kN
What type of bond is formed when there exists some form of collective interactions between the (negatively charged) electrons and (positively charged) nuclei in a solid?
Ionic
Covalent
Metallic
Van der Waals
Permanent magnets can be found in
electric bells
earphones
relays
dy namic loudspeakers
The phenomenon that when an electric current passes through an anisotropic crystala there is an absorption or liberation of heat due to the non-uniformity in current distribution.
Bridgman effect
Corona effect
Dember effect
Destriau effect
What principle states that each electron in an atom must have a different set of quantum numbers?
Inclusion principle
Exclusion principle
Quantum principle
Electron principle
One electron volt (1 eV) is equivalent to _____ joules
1.3 x 10^-19
1.4 x 10^-19
1.5 x 10^-19
1.6 x 10^-19
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
Which of the following materials has the least hysteresis loop area?
soft iron
silicon steel
hard steel
wrought iron
Ohm's law can be used only to a _____ circuit or component.
Unilateral
Exponential
Trivalent
Linear
The reluctance of the magnetic circuit is ________ relative permeability of the material comprising the circuit.
directly proportional to
inversely proportional to
independent of
dependent of
The greater percentage of materials is _________.
diamagnetic
paramagnetic
ferromagnetic
non-magnetic
Permeance is analogous to
Conductance
Reluctance
Admittance
Resistance
The unit of flux density is
Wb/m
Tesla
At/m
N/Wb
There are how many compounds available in nature?
300a000
Unlimited
States that the ratio of the thermal conductivity is proportional to the absolute temperature for all metals.
Wien's displacement law
Hartleys law
Hall's law
Wiedemann Franz law
If the right handed bottle-opener cork screw is assumed to be along the conductor so as to advance in the direction of current flow, the motion of its handle will indicate the direction of magnetic flux produced around the conductor. This is known as
Right hand rule
Left hand rule
Cork screw rule
End rule
The temperature coefficient of resistance of semiconductors is
positive
zero
negative
infinite
Permeance of a magnetic circuit is _________ the cross-sectional area of the circuit.
directly proportional to
inversely proportional to
dependent of
independent of
Who developed the electromagnetic theory of light in 1862?
Heinrich Rudolf Hertz
Wilhelm Rontgen
James Clerk Maxwell
Andre Ampere
Three charges of +5 Ca -6 C and +9 C are placed inside a sphere. What is the total flux passing through the surface of sphere?
8 C
14 C
20 C
-6 C
If the number of valence electrons of an atom is less than 4a then the substance is probably
a metal
an insulator
a non-metal
a semiconductor
Materials whose permeabilities are slightly greater than that of free space
Paramagnetic
Non- magnetic
Ferromagnetic
Diamagnetic
Hysteresis loss can be reduced by one of the following.
Increasing mmf of the circuit
Using material narrow hysteresis loop
Using ferromagnetic core
Laminating the magnetic circuit
The relative permeability of a magnetic material is 10^5. What is its permeability?
4 × 10^5 H/m
4 × 10^-12 H/m
4× 10^-2 H/m
4 × 10^7H/m
Electromotive force in a circuit
causes free electrons to flow
increases the circuit resistance
maintains circuit resistance
is needed to make the circuit complete
One oersted (Oe) is equivalent to _____ Gb/cm.
A substance that attracts pieces iron
Conductor
Semiconductor
Magnet
All of the above
Hysteresis refers to the ______ between flux density of the material and the magnetizing force applied.
Leading effect
Ratio
Equality
Lagging effect
The tiniest element of matter
Atom
Proton
Electron
Neutron
The uncharged particles which have no effect on its atomic charge.
Nucleons
Electrons
Protons
Neutrons