The straight line passing through the two poles of magnet is called
Real axis
Cartesian axis
Magnetic axis
Imaginary axis
Correct Answer :
C. Magnetic axis
Related Questions
Who demonstrated the theory of electromagnetic induction in 1831?
Michael Faraday
Andre Ampere
James Clerk Maxwell
Charles Coulomb
Which of the following magnetic materials can be easily magnetized in both direction?
Soft magnetic materials
Hard magnetic materials
High hysteresis loss materials
Low hysteresis loss materials
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
______ is an electromagnet with its core in the form of a close magnetic ring.
S olenoid
Paraboloid
Toroid
Cycloid
The hot resistance of an incandescent lamp is about _______ its cold resistance.
10 times
100 times
5 times
50 times
The science of adapting electronics to aerospace flight.
Avionics
Aerotronics
Aerodynamics
Astrionics
A factor used to correct for the electrostatic forces of the more distant ions in an ionic solid.
Avogadro's number
Planck's constant
Boltzmann's constant
Madelung constant
The magnitude of the induced emf in a coil is directly proportional to the rate of change of flux linkages. This is known as
Joule's Law
Faraday's second law of electromagnetic induction
Faraday's first law of electromagnetic induction
Coulomb's Law
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
What is the SI unit of conductivity?
Ohms/m
Ohms-m
Siemens-m
Siemens/m
When the current flowsa the magnetic field ��. conductor is in what direction?
The same as the current direction
Opposite the current direction
Omnidirectional
In the direction determined by the left hand rule
A substance that attracts pieces iron
Conductor
Semiconductor
Magnet
All of the above
The lagging effect between flux density of the material and the magne
Permeance
Eddy current
Hysteresis
R eluctance
Core materials of a good relay have _________ hysteresis loop.
large
narrow
very large
very narrow
An atom or a group of atoms that carries a net electric charge.
Positive ion
Negative ion
Ion
Electron
When a current carrying conductor is placed in a magnetic fielda the maximum force will act on the conductor when the conductor is at an angle of _______ to the magnetic field.
45o
60o
30o
90o
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
Why is it that the magnitude of magnetomotive force required for air gap is much greater than that required for iron part of a magnetic circuit?
Because air is a gas
Because air has the highest relative permeability
Because air is a conductor of magnetic flux
Because air has the lowest relative permeability
What determines the atomic number of an element?
The number of protons
The number of electrons
The number of neutrons
The number of neutrons and protons
A magnetic field is
The current flow through space around a permanent magnet
The force set up when current flows through a conductor
The force that drives current through a resistor
The force between the plates of a charged capacitor
Temporary magnets are commonly employed in
electric instruments
motors
moving coils loudspeakers
magnetos
One farad equals
1 coulomb/volt
1 newton/coulomb
1 newton-meter
1 volt/second/ampere
A 200-watt lamp working for 24 hours will consume approximately _____ units.
Who developed the electromagnetic theory of light in 1862?
Heinrich Rudolf Hertz
Wilhelm Rontgen
James Clerk Maxwell
Andre Ampere
Back emf refers to the
Current equal to the applied emf
Opposing emf
Current opposing the applied emf
Voltage opposing the applied emf
The force of attraction or repulsion between two magnetic poles is directly proportional to their strengths.
Newton's first law
Faraday's first law of electromagnetic induction
Coulomb's first law
Coulomb's second law
The magnetic potential in a magnetic circuit can be measured in terms of
Mmf
Emf
Farad
Coulomb
A good conductor has how many valence electrons?
What bond is formed when one or more electrons in the outermost energy orbit of an atom are transferred to another?
Ionic
Covalent
Metallic
Van der Waals
__________ is a substance of whose molecules consist of the same kind of atom.
Mixture
Compound
Element
Isotope