Description : What is the term used to refer to the losses which can be traced to the dielectric of a capacitor?
Last Answer : Power losses.
Description : Due to which of the following reasons the cables should not be operated too hot ? (a) The oil may loose its viscosity and it may start drawing off from higher levels (b) Expansion of the ... instability may rise due to the rapid increase of dielectric losses with temperature (e) All of the above
Last Answer : (e) All of the above
Description : Emulsifier protection is associated with: a) Grounding protection b) Dielectric strength protection of cables and conductors c) Lightning protection d) Fire protection
Last Answer : Ans: D
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 : Dielectric constant will be high in a) Conductors b) Semiconductors c) Insulators d) Superconductors
Last Answer : c) Insulators
Description : Materials which can store electrical energy are called (A) magnetic materials. (B) semi conductors. (C) dielectric materials. (D) super conductors.
Last Answer : (C) dielectric materials.
Description : What is the most likely cause of losses in waveguide systems?
Last Answer : Improperly connected joints or damaged inner surface.
Description : The efficiency of a transformer is mainly dependent on (A) core losses. (B) copper losses. (C) stray losses. (D) dielectric losses.
Last Answer : Ans: A Core loss has prominent value over other losses
Description : Line losses in a distribution circuit are kept to a minimum by __________. A. adding rubber insulation conductors to the circuit B. using higher current and lower voltage C. increasing the number of thermal relays in the circuit D. using higher voltage and lower current
Last Answer : Answer: D
Description : What are the three types of line losses associated with transmission lines?
Last Answer : Copper, dielectric, and radiation.
Description : Name two types of power losses associated with a capacitor.
Last Answer : a. Hysteresis b. Dielectric leakage
Description : An electric heater draws 5 kW of power for continuous hot water generation in an industry. How much quantity of water in litres per min can be heated from 30oC to 85oC ignoring losses?. a) 1.3 b) 78.18 c) 275 d) none of the above
Last Answer : a) 1.3
Description : What is the result of an abrupt change in the size, shape, or dielectric of a waveguide?
Last Answer : Reflections.
Description : What is used as a dielectric in waveguides?
Last Answer : Air.
Description : How is the dielectric strength of an insulator determined?
Last Answer : By raising the voltage on a test sample until it breaks down.
Description : Define dielectric strength.
Last Answer : The ability of the insulation material to withstand potential difference.
Description : What amount of flat tape or round cord is required to single lace a group of conductors?
Last Answer : Two and one-half times the length of the longest conductor in the group.
Description : Besides presenting a neat appearance and supporting each other, what is the other purpose for lacing conductors?
Last Answer : To aid in tracing the conductors when alterations or repairs are required.
Description : Define the metal solvent action that takes place when copper conductors are soldered together.
Last Answer : The solder dissolves a small amount of the copper, which combines with the solder forming a new alloy; therefore, the joint is one common metal.
Description : Why are small-wattage soldering irons not used to solder large conductors?
Last Answer : Although its temperature is as high as the larger irons, it does not have thermal inertia.
Description : What happens to the H lines between the conductors of a coil when the conductors are close together?
Last Answer : The H lines cancel.
Description : State the reason for the establishment of a "unit size" for conductors.
Last Answer : To allow comparisons between conductors of different sizes and resistance.
Description : Name the three power losses in a transformer
Last Answer : Copper-loss, eddy-current loss, and hysteresis loss
Description : Losses caused by skin effect and the I2R (power) loss are classified as what type of loss?
Last Answer : Copper losses.
Description : In fiber-to-fiber connections, Fresnel reflection is one source of coupling losses. Light is reflected back into the source fiber and is lost. What causes Fresnel reflection?
Last Answer : A step change in refractive index that occurs at fiber joints, caused by fiber separation.
Description : Fiber-to-fiber coupling loss is affected by intrinsic and extrinsic coupling losses. Can intrinsic coupling losses be limited by limiting fiber mismatches?
Last Answer : Yes.
Description : How are source-to-fiber coupling and microbending and macrobending losses affected by changes in core diameter and D?
Last Answer : Coupling efficiency increases with both core diameter and D, while bending losses increase directly with core diameter and inversely with D.
Description : How is fiber sensitivity to bending losses reduced?
Last Answer : Fiber sensitivity to bending losses can be reduced if the refractive index of the core is increased and/or if the overall diameter of the fiber increases.
Description : Scattering losses are caused by the interaction of light with density fluctuations within a fiber. What are the two scattering mechanisms called when the size of the density fluctuations is (a) greater than and (b) less than one-tenth of the operating wavelength?
Last Answer : . (a) Mie scattering; (b) Rayleigh scattering.
Description : What causes copper losses?
Last Answer : Resistance in the armature coils, which increases with temperature
Description : What is the advantage of directly heated cathodes?
Last Answer : They reach operating temperatures quickly.
Description : What happens to the resistance of copper when it is heated?
Last Answer : It increases.
Description : _________is a form of non-volatile storage that operates by changing the resistance of a specially formulated solid dielectric material. A. VRAM B. WRAM C. MRAM D. RRAM
Last Answer : D. RRAM Resistive RAM
Description : The 'dielectric constant' is a numerical value indicating the effectiveness of a dielectric material in comparison to that of a standard, which is _______________. A. paper or cloth B. glass or mica C. plastic or Teflon D. dry air or a vacuum
Description : A 'dielectric' is a/an ________________. A. electrical insulator B. current flow C. good conductor D. semiconductor material
Last Answer : Answer: A
Description : Referred to the dielectric constant of a transmission line material. A. Inductance and capacitance B. Velocity factor C. Characteristic impedance D. Propagation velocity
Last Answer : B. Velocity factor
Description : ECE Board Exam March 1996 That dielectric material of an optical fiber surrounding the core A. Cladding B. Armor C. Shield D. Cover
Last Answer : A. Cladding
Description : Dielectric strength of a material is (A) Its energy storage capacity (B) A magnetic property (C) Its capacity to resist the flow of current (D) Its capacity to withstand high voltage
Last Answer : (D) Its capacity to withstand high voltage
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 : 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 : Dielectric property impacts the behaviour of a material in the presence of electric field. State True/False. a) True b) False
Last Answer : a) True
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 : 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 : Dielectric (A) Is an electrical insulating material (B) Of low resistivity is preferred (C) Should have high thermal conductivity (D) Need not defy the corrosive action of chemicals
Last Answer : (A) Is an electrical insulating material
Description : Which of the following is not a dielectric material? (A) Cotton, silk and paper (B) Asbestos, glass, porcelain and mica (C) Rubber and polymeric resins (D) All refractory materials
Last Answer : Option C
Description : The insulating material should have (a) low permittivity (b) high resistivity (c) high dielectric strength (d) all of the above
Last Answer : (d) all of the above
Description : The insulating material for a cable should have (a) low cost (b) high dielectric strength (c) high mechanical strength (d) all of the above
Description : The size, shape, and dielectric material of a waveguide must be constant throughout its length for energy to move from one end to the other without reflections. What could be the effect in any abrupt change in its size or shape?
Description : Thevelocityfactor of a transmissionline a. depends on the dielectric constant of the material used b. increases the velocity along the transmission line c. is govern by the skin effect d. is higher for a solid dielectric than for air
Last Answer : a. depends on the dielectric constant of the material used