Description : Ceramics are good (A) insulators. (B) conductors. (C) superconductors. (D) semiconductors.
Last Answer : (A) insulators.
Description : Materials exhibiting zero value of resistivity are known as ______ . (a) conductors (b) semiconductors (c) insulators (d) superconductors
Last Answer : (d) superconductors
Description : The skin effect is a phenomenon observed in a) Insulators b) Dielectrics c) Conductors d) Semiconductors
Last Answer : c) Conductors
Description : Skin depth phenomenon is found in which materials? a) Insulators b) Dielectrics c) Conductors d) Semiconductors
Description : Holes are majority carriers in (A) P-type semiconductors. (B) N-type semiconductors. (C) Insulators. (D) Superconductors.
Last Answer : (A) P-type semiconductors.
Description : For a dielectric which of the following properties hold good? a) They are superconductors at high temperatures b) They are superconductors at low temperatures c) They can never become a superconductor d) They have very less dielectric breakdown voltage
Last Answer : b) They are superconductors at low temperatures
Description : Substances of conductivity between 10–10 10–20 (n m )–1 are: a) Insulators b) Semiconductors c)Super conductors d)Good conductors
Last Answer : a) Insulators
Description : he substances of conductivity of the order of 10–6 – 10–4 (m)–1 are : a) Insulators b) Super conductors c) Semiconductors d)Good conductors
Last Answer : d)Good conductors
Description : Czochralski method is widely used for the growth of crystal of -------------materials. a) Conductors b) semiconductors c) insulator d) conductors & insulators
Last Answer : b) semiconductors
Description : Classify the solids into conductors, semiconductors and insulators on the basis of band theory of solids.
Last Answer : In conductors there is no energy gap between valance band and conduction band, they are overlapped on each other. So electrons can jump from valance band to conduction band easily and material ... band when some amount of energy is supplied to it. Therefore insulators cannot conduct the current.
Description : Name two good conductors, two good insulators, and two semiconductors.
Last Answer : In general all metals are good conductors, with silver the best and copper second.
Description : Both the conduction and displacement current densities coexist in which medium? a) Only conductors in air b) Only dielectrics in air c) Conductors placed in any dielectric medium d) Both the densities can never coexist
Last Answer : c) Conductors placed in any dielectric medium
Description : Superconductors are those elements – (1) Whose conductivity is intermediate between metals and insulators (2) Whose resistance falls almost to zero at very low temperature (3) Which conduct electricity only at super-high temperature (4) Which conduct electricity only, at super-high temperatures
Last Answer : (2) Whose resistance falls almost to zero at very low temperature Explanation: Superconductivity is a phenomenon of exactly zero electrical resistance and expulsion of magnetic fields occurring in ... lines from the interior of the superconductor as it transitions into the superconducting state.
Description : Superconductors are those elements (1) Whose conductivity is intermediate between metals and insulators (2) Whose resistance falls almost to zero at very low temperatures (3) which turn into insulators at very low temperatures (4) which conduct electricity only at super-high temperatures
Last Answer : Whose resistance falls almost to zero at very low temperatures
Description : Ceramic materials possess which of the following properties? a) Brittle and low dielectric constant b) Rigid and low dielectric constant c) Brittle and high dielectric constant d) Rigid and high dielectric constant
Last Answer : c) Brittle and high dielectric constant
Description : Superconductors exhibit which of the following properties? a) Ferromagnetism b) Polarisation c) Diamagnetism d) Ferrimagnetism
Last Answer : c) Diamagnetism
Description : Calculate the phase constant of a dielectric with frequency 6 x 10 6 in air. a) 2 b) 0.2 c) 0.02 d) 0.002
Last Answer : c) 0.02
Description : Calculate the loss tangent when the dielectric constant in AC field is given by 3 + 2j. a) (2/3) b) (3/2) c) (-3/2) d) (-2/3)
Last Answer : d) (-2/3)
Description : Compute the refractive index when the dielectric constant is 256 in air. a) 2562 b) 16 c) 256 d) 64
Last Answer : b) 16
Description : Polarizability is defined as the a) Product of dipole moment and electric field b) Ratio of dipole moment to electric field c) Ratio of electric field to dipole moment d) Product of dielectric constant and dipole moment
Last Answer : b) Ratio of dipole moment to electric field
Description : The ratio of conduction to displacement current density is referred to as a) Attenuation constant b) Propagation constant c) Loss tangent d) Dielectric constant
Last Answer : c) Loss tangent
Description : Find the dielectric constant for a material with electric susceptibility of 4. a) 3 b) 5 c) 8 d) 16
Last Answer : b) 5
Description : Find the susceptibility of a material whose dielectric constant is 2.26. a) 1.26 b) 3.26 c) 5.1 d) 1
Last Answer : a) 1.26
Description : The permittivity is also called a) Electrostatic energy b) Dielectric constant c) Dipole moment d) Susceptibility
Last Answer : b) Dielectric constant
Description : In conductors, which two parameters are same? a) Wavelength and phase constant b) Phase and attenuation constant c) Attenuation constant and skin depth d) Skin depth and wavelength
Last Answer : b) Phase and attenuation constant
Description : Semiconductors possess which type of bonding? a) Metallic b) Covalent c) Ionic d) Magnetic
Last Answer : b) Covalent
Description : Transistors are made from (a) Plastic (b) metals (c)insulators (d) doped semiconductors
Last Answer : d) doped semiconductors
Description : Magnetic materials (A) provide path to magnetic flux. (B) are good insulators. (C) are semiconductors. (D) None.
Last Answer : (A) provide path to magnetic flux.
Description : Insulators perform which of the following functions? a) Conduction b) Convection c) Provide electrical insulation d) Allows current leakage at interfaces
Last Answer : c) Provide electrical insulation
Description : A perfect dielectric acts as a a) Perfect transmitter b) Perfect reflector c) Bad transmitter d) Bad reflector
Last Answer : a) Perfect transmitter
Description : The attenuation in a good dielectric will be non- zero. State True/False. a) True b) False
Last Answer : a) True
Description : The permeability of a dielectric material in air medium will be a) Absolute permeability b) Relative permeability c) Product of absolute and relative permeability d) Unity
Last Answer : a) Absolute permeability
Description : The total permittivity of a dielectric transformer oil (relative permittivity is 2.2) will be (in order 10 -11 ) a) 1.94 b) 19.4 c) 0.194 d) 194
Last Answer : a) 1.94
Description : The loss tangent of a perfect dielectric will be a) Zero b) Unity c) Maximum d) Minimum
Last Answer : d) Minimum
Description : An example for lossless propagation is a) Dielectric waveguide propagation b) Conductor propagation c) Cavity resonator propagation d) It is not possible
Last Answer : d) It is not possible
Description : In lossy dielectric, the phase difference between the electric field E and the magnetic field H is a) 90 b) 60 c) 45 d) 0
Last Answer : d) 0
Description : For a lossless dielectric, the attenuation will be a) 1 b) 0 c) -1 d) Infinity
Last Answer : b) 0
Description : For a perfect dielectric, which parameter will be zero? a) Conductivity b) Frequency c) Permittivity d) Permeability
Last Answer : a) Conductivity
Description : For a dielectric, the condition to be satisfied is a) σ/ωε > 1 b) σ/ωε < 1 c) σ = ωε d) ωε = 1
Last Answer : b) σ/ωε < 1
Description : The loss tangent refers to the a) Power due to propagation in conductor to that in dielectric b) Power loss c) Current loss d) Charge loss
Last Answer : a) Power due to propagation in conductor to that in dielectric
Description : Will dielectric breakdown lead to formation of magnetic monopole? a) Yes b) No
Last Answer : b) No
Description : The Gauss law for magnetic field is valid in a) Air b) Conductor c) Dielectric d) All cases
Last Answer : d) All cases
Description : In dielectric medium, the Maxwell second equation becomes a) Curl(H) = Jd b) Curl(H) = Jc c) Curl(E) = Jd d) Curl(E) = Jd
Last Answer : a) Curl(H) = Jd
Description : Compute the conductivity when the current density is 12 units and the electric field is 20 units. Also identify the nature of the material. a) 1.67, dielectric b) 1.67, conductor c) 0.6, dielectric d) 0.6, conductor
Last Answer : c) 0.6, dielectric
Description : Compute the loss factor when the loss tangent is 0.88 and the real part of dielectric is 24. a) 12.12 b) 12.21 c) 21.21 d) 21.12
Last Answer : d) 21.12
Description : Choose the best definition of dielectric loss. a) Absorption of electric energy by dielectric in an AC field b) Dissipation of electric energy by dielectric in a static field c) Dissipation of heat by dielectric d) Product of loss tangent and relative permittivity
Last Answer : a) Absorption of electric energy by dielectric in an AC field
Description : When a dielectric loses its dielectric property, the phenomenon is called a) Dielectric loss b) Dielectric breakdown c) Polarisation d) Magnetization
Last Answer : b) Dielectric breakdown
Description : Dielectric property impacts the behaviour of a material in the presence of electric field. State True/False. a) True b) False
Description : Which of the following is not an example of elemental solid dielectric? a) Diamond b) Sulphur c) Silicon d) Germanium
Last Answer : c) Silicon
Description : Calculate the energy stored per unit volume in a dielectric medium due to polarisation when P = 9 units and E = 8 units. a) 1.77 b) 2.25 c) 36 d) 144
Last Answer : c) 36