Description : A perfect conductor acts as a a) Perfect transmitter b) Perfect reflector c) Bad transmitter d) Bad reflector
Last Answer : b) Perfect reflector
Description : The loss tangent of a perfect dielectric will be a) Zero b) Unity c) Maximum d) Minimum
Last Answer : d) Minimum
Description : For a perfect dielectric, which parameter will be zero? a) Conductivity b) Frequency c) Permittivity d) Permeability
Last Answer : a) Conductivity
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 : 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 : 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 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 : 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 : 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 : 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 : Dielectric property impacts the behaviour of a material in the presence of electric field. State True/False. a) True b) False
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 : 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
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 : If the loss tangent is very less, then the material will be a a) Conductor b) Lossless dielectric c) Lossy dielectric d) Insulator
Last Answer : b) Lossless dielectric
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 : 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 : 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 : A dielectric can be made a conductor by a) Compression b) Heating c) Doping d) Freezing
Last Answer : b) Heating
Description : Identify a good dielectric. a) Iron b) Ceramics c) Plastic d) Magnesium
Last Answer : b) Ceramics
Description : A dielectric is always an insulator. But an insulator is not necessarily a dielectric. State True/False. a) True b) False
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 : Under the influence of electric field, the dielectric materials will get charged instantaneously. State True/False. a) True b) False
Description : Dielectric constant will be high in a) Conductors b) Semiconductors c) Insulators d) Superconductors
Last Answer : c) Insulators
Description : The permittivity is also called a) Electrostatic energy b) Dielectric constant c) Dipole moment d) Susceptibility
Last Answer : b) Dielectric constant
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 : Two small diameter 10gm dielectric balls can slide freely on a vertical channel. Each carry a negative charge of 1μC. Find the separation between the balls if the lower ball is restrained from moving. a) 0.5 b) 0.4 c) 0.3 d) 0.2
Last Answer : c) 0.3
Description : Example of spherical system in the following is a) Charge in space b) Charge in box c) Charge in dielectric d) Uncharged system
Last Answer : a) Charge in space
Description : The angle of incidence is equal to the angle of reflection for perfect reflection. State True/False. a) True b) False
Description : In perfect conductors, the phase shift between the electric field and magnetic field will be a) 0 b) 30 c) 45 d) 90
Last Answer : c) 45
Description : A white and smooth surface is – (1) good absorber and good reflector of heat (2) bad absorber and good reflector of heat (3) good absorber and bad reflector of heat (4) bad absorber and bad reflector of heat
Last Answer : (2) bad absorber and good reflector of heat Explanation: Shiny surfaces are poor absorbers of heat radiation and the best reflectors of heat radiation. Black surfaces are the best emitters and best absorber of heat radiation.
Description : The earth is a – (1) good reflector of heat (2) non-absorber of heat (3) good absorber and good radiator of heat (4) bad absorber and bad radiator of heat
Last Answer : (3) good absorber and good radiator of heat Explanation: The earth's surface radiates as a black body, since it aborts and radiates with nearly 100 percent efficiency for its temperatures. Gases, on the contrary, are selective absorbers and radiators.
Description : A white and smooth surface is (1) good absorber and good reflector of heat (2) bad absorber and good reflector of heat (3) good absorber and bad reflector of heat (4) bad absorber and bad reflector of heat
Last Answer : bad absorber and good reflector of heat
Description : The earth is a (1) good reflector of heat (2) non-absorber of heat (3) good absorber and good radiator of heat (4) bad absorber and bad radiator of heat
Last Answer : Bad absorber and bad radaitor because all bad absorber are bad emitter. As well
Description : What vswr is a perfect match between a transmitter and its load?
Last Answer : 1 to 1.
Description : Methyldopa lowers BP by: A. Inhibiting dopa decarboxylase in adrenergic nerve endings B. Generating α-methyl noradrenaline in brain which reduces sympathetic tone C. Generating α-methyl ... as a false transmitter in peripheral adrenergic nerve endings D. Activating vascular dopamine receptors
Last Answer : B. Generating α-methyl noradrenaline in brain which reduces sympathetic tone
Description : An automobile needs an antenna for its radio to play properly because: w) the automobile's tires insulate it from the ground. x) the automobile's body acts as a Faraday cage. y) when the ... signal appears changed with respect to when it is at rest. z) the transmitter also uses an antenna.
Last Answer : ANSWER: X -- THE AUTOMOBILE'S BODY ACTS AS A FARADAY CAGE.
Description : A body will behave as an “ideal black body” when it acts as: a) A perfect absorber b) A perfect radiator c) A body to have absorption power equal to one d) All of the above
Last Answer : d) All of the above