When the relative permeability of a material is slightly more than 1a it is called ______ material.
diamagnetic
ferromagnetic
paramagnetic
non-magnetic
Correct Answer :
C. paramagnetic
Related Questions
How many turns are needed to produce a magnetomotive force of 1000 A.t for a coil with 6 amperes?
6000 turns
600 turns
167 turns
67turns
In electro-mechanical conversion devices like generators and motors the reason why a small air gap is left between the rotor and stator is to
permit mechanical clearance
increase flux density in air gap
decrease the reluctance of magnetic path
complete the magnetic path
The ability of a material to conduct magnetic flux through it.
Permittivity
Reluctivity
Conductivity
Permeability
The force between two magnetic poles is _____ their poles strength.
equal to
directly proportional to
inversely proportional to
directly proportional to the square root of
Which of the following is a vector quantity?
Magnetic potential
Magnetic field intensity
Magnetic permeability
F lux density
What is the cgs unit of magnetomotive force?
Gilbert
Ampere- turn
Maxwell
Weber
The ratio of the total flux (flux in iron path) to the useful flux (flux in air gap)
Leakage flux
Leakage current
Leakage coefficient
Leakage factor
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
Permeability means
The conductivity of the material for magnetic lines of force
The magnetization test in the material after exciting field has been removed
The strength of an electromagnet
The strength of the permanent magnet
Defined as the ratio of the volume occupied by the atoms or ions in a unit cell divided by the volume of the unit cell and is used to measure the compactness of a crystal.
Atomic packing factor (APF)
Ionic Packing Ratio (IPR)
Atomic compacting factor (ACF)
Ionic compacting ratio (ICR)
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
Residual magnetism refers to the flux densitya which exists in the iron core when the magnetic field intensity is
Minimized
Reduced to zero
Maximize
Unity
A permanent magnet does not exert a force on
an unmagnetized iron bar
a magnetized iron bar
a moving electric charge
a stationary electric charge
Magnetic fields do not interact with
Moving permanent magnets
Stationary permanent magnets
Moving electric charges
Stationary electric charges
If the resistance of a material 2 m long and 2 m^2 in area of cross-section is 1.6 ×10^-8 ?a then its resistivity is
3.2 × 10^-8 ?-m
1.6 × 10^-8 ?-m
0.64 × 10^-8 ?-m
0.16 × 10^-8 ?-m
What is the unit of magnetomotive force?
Volt
Tesla
Ampere- turn
Weber
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
What is the practical unit of electrical energy?
Watt
Kilowatt-hour
Kilowatt-second
Megawathour
A theorem which states that an electric current flowing in a circuit produces a magnetic field at external points equivalent to that due to a magnetic shell whose bounding edge is the conductor and whose strength of the current.
Joule's law
Faraday's law
Volta's theorem
Ampere's theorem
Ohm's law cannot be applied to which material?
Copper
Silver
Silicon carbide
Aluminum
Which of the following is a paramagnetic material?
Carbon
Copper
Bismuth
Oxygen
Which element has four valence electrons?
Conductor
Insulator
Semiconductor
Semi- insulator
Which of the following is a natural magnet?
Steel
Magnesia
Lodestone
S oft iron
Electronic current in a wire is the flow of ____________ electrons.
free
valence
bound
loose
A good conductor has how many valence electrons?
What is the measure of the density and sign of the electric charge at a point relative to that at some time?
Electric potential
Electric charge
Electric current
Electric intensity
Electric field intensity at a point due to a given charge ______ if the relative permittivity of the medium decreases.
decreases
remains unchanged
increases
b ecomes zero
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
The temperature coefficient of resistance of conductors is
positive
zero
negative
infinite
A 200-watt lamp working for 24 hours will consume approximately _____ units.