Which of the following is a paramagnetic material?
Carbon
Bismuth
Copper
Oxygen
Correct Answer :
D. Oxygen
Related Questions
Used to maintain strength of magnetic field
Container
Air gap
Keeper
S ource
Which of the following statements is TRUE?
Silicon dioxide is a good
The current carriers in conductors are valence electrons
For conductorsa the valence electron are strongly attracted to the nucleus
The valence electrons are located in the nucleus of an atom
Hydrogen is an example of a _____ material.
Paramagnetic
Diamagnetic
Ferromagnetic
N on- magnetic
The amount of magnetizing force to counter balance the resid magnetic material is referred to as
Reluctivity
Susceptivity
Coercivity
Retentivity
What bond is formed when electrons in the outermost energy orbits of the atoms are shared between two or more electrons?
Ionic
Covalent
Metallic
Van der Waals
The ability of a material to conduct magnetic flux through it.
Permittivity
Reluctivity
Conductivity
Permeability
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
Which of the following has the highest permeability?
Soft iron
Steel
Air
Permalloy
Paramagnetic substance has a relative permeability of
Slightly less than one
Equal to one
Slightly equal to one
Very much greater than one
Which of the following has the least number of valence electrons?
Conductor
Semiconductor
Insulator
Semi- insulator
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
When the relative permeability of a material is slightly more than 1a it is called ______ material.
diamagnetic
ferromagnetic
paramagnetic
non-magnetic
The hot resistance of an incandescent lamp is about _______ its cold resistance.
10 times
100 times
5 times
50 times
If a 20 V potential is applied across a relay coil with 50 turns having 1 ? of resistancea the total magnetomotive producing magnetic flux in the circuit is
10 Wb
50 T
1000 A t/m
1000,t
A 200-watt lamp working for 24 hours will consume approximately _____ units.
If the value of 25 a conductor is 1/255 per oCa then the value of 20is
1/300 per oC
1/250 peroC
1/230 per oC
1/260 per oC
The simplest type of atom to exist is the ______ atom.
Helium
Hydrogen
Boron
Oxygen
Formed when there exist distant electronic interactions between (opposite) charges present in the neighboring atoms or molecules.
Ionic bond
Covalent bond
Metallic bond
Van der Waals bond
The temperature coefficient of resistance of a conductor ______ with an increase in temperature.
increases
decreases
remains the same
becomes negative
If on looking at any one end of a solenoid; the direction of current flow is found to be clockwise then the end under observation is a south pole. This is known as
Right hand rule
Left hand rule
Cork screw rule
End Rule
The ratio between the intensity of magnetization produced in a substance to the magnetizing force producing it
Magnetic Reluctivity
Magnetic Resistivity
Magnetic susceptibility
Magnetic conductivity
If the value of 0 a conductor is 1/234 per oCa then the value of 18is
1/218 per oC
1/252 peroC
1/272 per oC
1/273 per oC
If a magnetic flux cuts across 200 turns at a rate of 2Wb/sa the induced voltage according to Faraday's law is about
400 V
100 V
200 V
600 V
What is the unit of reluctance?
Maxwell
Gauss
At/Wb
Weber
The force between two magnetic poles varies with the distance between them. The variation is ______ to the square of that distance.
Equal
Greater than
Directly proportional
Inversely proportional
A length of wire has a resistance of 10 ohms. What is the resistance of a wire of the same material three times as long and twice the cross-sectional area?
30 ohms
20 ohms
15 ohms
7 ohms
The conduction of electricity across the surface of a dielectric is called
creepage
skin effect
surface effect
crosstalk
The ratio of the permeability of material to the permiabiity of air or vacuum.
Relative permeability
Relative permittivity
Relative conductivity
Relative reluctivity
If the number of valence electrons of an atom is more than 4a the substance is called
a semiconductor
a conductor
an insulator
a semi-insulator
Under ordinary conditionsa a body is considered
positively charged
neutral
negatively charged
stable