Worksheets16PH212-Materials Science (PART 1)
Total questions: 50
Worksheet time: 25mins
What will happen with magnetic materials is kept in external magnetic field?
They will move
They will develop magnetic lines of force
They will create a permanent magnetic moment
They will be unaffected
How is the residual magnetism from a material removed?
Retentivity
Coercivity
Magneton
Switching off magnetic field
In which of the following magnetic moment is zero?
Dia-magnetic material
Parra-magnetic material
Ferromagnetic material
Ferrimagnetic material
The susceptibility is independent of temperature in which material?
Paramagnetic
Ferromagnetic
Diamagnetic
Ferrimagnetic
What is the name of the continuous curve in magnetic field, the tangent of which gives the direction of magnetic intensity?
Magnetic lines of force
Magnetic lines of induction
Magnetic force
Magnetic dipole moment
Which of the following is a strong magnet?
Diamagnetic material
Paramagnetic material
Antiferromagnetic material
Ferromagnetic material
What is the material used in two port device?
Ferromagnets
Ferrites
Antiferromagnets
Paramagnets
The magnetization is defined by the ratio of
Magnetic moment to area
Magnetic moment to volume
Magnetic flux density to area
Magnetic flux density to volume
With increase in the area of hysteresis curve, power loss will
Increases
Decreases
First decreases then increases
First increases then decreases
Permanent magnets are made of
Soft magnetic materials
Hard magnetic materials
semiconductors
super conductors
The critical temperature above which the ferromagnetic materials lose their magnetic property is known as
hysteresis
curie point
transition temperature
standard temperature
Materials, which provide a path to the magnetic flux, are classified as
insulating materials
semi conducting materials
magnetic materials
dielectric materials
The relative permeability of a paramagnetic substance is
unity
slightly more than unity
zero
less than unity
The ratio between absolute permeability of a medium to permeability of a free space is called as
Magnetic susceptibility
Relative permeability
Magnetic permeability
Magnetic field strength
The Magnetization possessed by the magnetic material even after the removal of the external magnetic field is called as
Coercivity
Retentivity
motion of domain walls
rotation of domain walls
The Magnetic moment per unit volume of the material is called as
Magnetic flux density
Intensity of Magnetization
Magnetic flux
Magnetic induction
In ___________material, the direction of the induced dipole moment is opposite to that of externally applied magnetic field.
Ferromagnetic
Paramagnetic
Antiferromagnetic
Diamagnetic
Magnetic Hysteresis is nothing but
lagging of magnetic flux behind applied field
lagging of magnetic induction behind applied field
lagging of applied field behind magnetic flux
lagging of applied field behind magnetic induction
Example for ferri-magnetic materials
salts of transition elements
rare earth elements
transition metals
Ferrites
The domain theory of ferromagnetism was proposed by
Curie
Ronald
Weiss
Einstein
“Tesla” is as same as
Weber-metre
Weber/metre
Weber/metre2
Weber-metre2
Weber is the unit of
Magnetic field strength
Magnetic induction
Magnetic flux
absolute permeability
Example for para-magnetic materials
super conductors
alkali metals
transition metals
Ferrites
Example for ferro-magnetic materials
super conductors
alkali metals
transition metals
Ferrites
Which among the following statements are true?
i) Interaction between the neighboring dipoles is negligible in the case of ferromagnetic material.
ii) In ferromagnetic material the number of electrons with opposite spin in unequal.
iii) Magnetic moment due to orbital motion of an electron is called Bohr magneton
iv) In a ferromagnetic material, susceptibility is very large and positive
i and iii
ii and iv
iii and iv
iv and i
Example for dia-magnetic materials
super conductors
alkali metals
transition metals
Ferrites
Magnetic field strength’s units are
Wb / m2
Wb / A.m
A / m
Tesla / m
Example for magnetic material used in data storage devices
45 Permalloy
CrO2
Cunife
Alnico
Pick the paramagnetic material from the below listed materials_________
Oxygen
Iron
Wood
Plastic
Hysteresis loop is a graph between_________
Magnetic induction B vs. Applied magnetic field H
Magnetic susceptibility Vs. Temperature
Magnetic susceptibility Vs. Magnetic Permeability
Magnetic moment Vs. Curie temperature
The _________ material has sharp decrease in susceptibility at Neel temperature
Dia
Para
Ferro
Antiferro
The Ferromagnetism in materials is due to
partially filled 3d orbitals
completely filled 3d orbitals
partially filled 2d orbitals
completely filled 2d orbitals
_______ has magnetic moment of antiparallel and of different magnitudes
Dia magnetic material
Para magnetic material
Ferro magnetic material
Ferrites
_________ magnetic materials has high Retentivity and Coercivity
Antiferromagnetic
Soft
Hard
Ferromagnetic
The easy axis of magnetization in Fe (bcc) single crystal is
[100]
[111]
[110]
[101]
Ferromagnetism can be explained on the basis of
quantum theory
neutron theory
domain theory
kinetic theory of gases
Which of the following is a vector quantity?
Relative permeability
Magnetic field intensity
Flux density
Magnetic potential
Ferrites are a sub-group of
non-magnetic materials
ferro-magnetic materials
paramagnetic materials
ferri-magnetic materials
What is the process of producing electric dipoles inside the dielectric by an external electric field?
Polarisation
Dipole moment
Susceptibility
Magnetisation
Which of the following easily adapt itself to store electrical energy?
Passive dielectric
Superconductor
Active dielectric
Polar molecules
How does ionic polarisation occur?
Splitting of ions
Passing magnetic field
Displacement of cations and anions
Never occurs
Which of the following polarisations is very rapid?
Electronic polarisation
Ionic polarisation
Space charge polarisation
Orientation polarisation
Which of the following is the slowest polarisation method?
Ionic polarisation
Orientation polarisation
Electronic polarisation
Space charge polarisation
Which of the following breakdowns occur at higher temperature?
Avalanche breakdown
Thermal breakdown
Electrochemical breakdown
Dielectric breakdown
Which of the following materials exhibit Ferro-electricity?
Iron
Platinum
Hydrogen
Rochelle salt
Identify a good dielectric
Iron
Ceramics
Plastic
Magnesium
A dielectric can be made a conductor by
Compression
Heating
Doping
Freezing
When a dielectric loses its dielectric property, the phenomenon is called
Dielectric loss
Dielectric breakdown
Polarisation
Magnetization
At equilibrium, the Lorentz force and the Coulomb force are _____ to each other
equal and opposite
not equal
equal
effective
Dipole moment is _________ the electric field strength (E)
directly proportional
inversely proportional
independent of
depend on
