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 : What is the most likely cause of losses in waveguide systems?
Last Answer : Improperly connected joints or damaged inner surface.
Description : Name the three power losses in a transformer
Last Answer : Copper-loss, eddy-current loss, and hysteresis loss
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 : What types of losses cause the dielectric material between the conductors to be heated?
Last Answer : Dielectric losses.
Description : Losses caused by skin effect and the I2R (power) loss are classified as what type of loss?
Last Answer : Copper losses.
Description : What are the three types of line losses associated with transmission lines?
Last Answer : Copper, dielectric, and radiation.
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 : Name two types of power losses associated with a capacitor.
Last Answer : a. Hysteresis b. Dielectric leakage
Description : Which of the following losses is/are present in every direct current generator armature? A. Winding copper loss B. Core eddy current loss C. Magnetic hysteresis loss D. All of the above.
Last Answer : Answer: D
Description : A cable carrying alternating current has (a) hysteresis losses only (b) hysteresis and leakage losses only (c) hysteresis, leakage and copper losses only (d) hysteresis, leakage, copper and friction losses
Last Answer : (b) hysteresis and leakage losses only
Description : The term power budgeting refers to ∙ A. the cost of cable, connectors, equipment and installation ∙ B. the loss of power due to defective components ∙ C. the total power available minus the attenuation losses ∙ D. the comparative costs of fiber and copper installations
Last Answer : C. the total power available minus the attenuation losses
Description : [75] Two transformers are connected in parallel. These transformers do not have equal percentage impedance which results A. Short-circuiting of the secondaries B. Power factor of one of the ... have negligible core losses D. Loading of the transformers not in proportion to their kVA ratings.
Last Answer : D. Loading of the transformers not in proportion to their kVA ratings
Description : 70] Silicon steel used in laminations mainly reduces A. Hysteresis loss B. Eddy current losses C. Copper loss D. All of the above
Last Answer : A. Hysteresis loss
Description : 64)During the short-circuit test on a small transformer the frequency is increased from 50-200Hz. The copper losses will increase by a factor of A. 16 B. 4 C. 1 D. 1/4
Last Answer : A) 16
Description : 45 The function of conservator in a transformer is A. To protect against internal fault B. To reduce copper as well as core losses C. To cool the transformer oil D. To take care of the expansion and contraction of transformer oil due to variation of temperature of surroundings
Last Answer : D. To take care of the expansion and contraction of transformer oil due to variation of temperature of surroundings
Description : 42 The efficiency of a transformer will be maximum when A. copper losses = hysteresis losses B. Hysteresis losses = eddy current losses C. Eddy current losses = copper losses D. Copper losses = iron losses
Last Answer : D. Copper losses = iron losses
Description : 8 The transformer core is laminated to A. Reduce the copper losses B. Reduce the core losses C. Reduce the eddy current losses D. None of the above
Last Answer : C. Reduce the eddy current losses
Description : The armature of a dc machine is laminated to reduce: (A) Eddy current loss (B) Hysteresis loss (C) copper losses (D) friction and windage losses
Last Answer : Ans: A Thinner the laminations, greater is the resistance offered to the induced e.m.f., smaller the current and hence lesser the I2R loss in the core.
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 : 7 The main advantage of auto transformer over a two winding transformer is A. Hysteresis losses are reduced B. Saving in winding material C. Copper losses are negligible D. Eddy losses are totally eliminated
Last Answer : A) hysteresis losses is reduced
Description : A 500 kVA, 3-phase transformer has iron losses of 300 W and full load copper losses of 600 W. The percentage load at which the transformer is expected to have maximum efficiency is (A) 50.0% (B) 70.7% (C) 141.4% (D) 200.0%
Last Answer : A 500 kVA, 3-phase transformer has iron losses of 300 W and full load copper losses of 600 W. The percentage load at which the transformer is expected to have maximum efficiency is 70.7%
Description : A transformer has maximum efficiency at 3/4 full load. The ratio of its iron losses and full load copper loss is : - a) 16/9 b) 4 / 3 c) 3/4 d) 9 /16
Last Answer : A transformer has maximum efficiency at 3/4 full load. The ratio of its iron losses and full load copper loss is : - 9 /16
Description : Auto-transformer makes effective saving on copper and copper losses, when its transformation ratio is?
Last Answer : Auto-transformer makes effective saving on copper and copper losses, when its transformation ratio is approximately equal to 1.
Description : What are 2 possible causes of lamb losses?
Last Answer : Not breathing, cold, starvation, pneumonia, scours, Navel Ill, entropion (inverted eyelids), urinary calculi (H2O belly)
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 : Conduction in which type of semiconductor material is similar to conduction in a copper wire?
Last Answer : N-type material.
Description : What procedure involves the use of finely braided copper wire to remove solder?
Last Answer : Wicking.
Description : A cylindrical copper block with resonant cavities around the circumference is used as what component of a magnetron?
Last Answer : Anode or plate
Description : Which wire has the least resistance? Wire A-copper, 1000 circular mils, 6 inches long. Wire B-copper, 2000 circular mils, 11 inches long.
Last Answer : Wire B.
Description : When would silver be used as a conductor in preference to copper?
Last Answer : When the need for conductivity is great enough to justify the additional expense.
Description : How can a sheet of copper be made to emit electrons thermionically?
Last Answer : By heating it.
Description : What happens to the resistance of copper when it is heated?
Last Answer : It increases.
Description : State four advantages of copper over aluminum as a conductor.
Last Answer : It has higher conductivity, it is more ductile, it has relatively high tensile strength, and it can be easily soldered.
Description : What causes the nuts or screws that hold the tips on soldering irons and guns to loosen?
Last Answer : The heating and cooling cycles.
Description : What causes a "fractured solder" joint?
Last Answer : Movement of the parts being soldered while the solder is cooling.
Description : The interaction between an external field and the binding force of an atom causes electrons to do what?
Last Answer : Wobble at a natural resonant frequency.
Description : What interaction causes energy to travel down a waveguide?
Last Answer : The interaction of the electric and magnetic fields.
Description : What causes the current-carrying area at the center conductor of a coaxial line to be restricted to a small layer at the surface?
Last Answer : Skin effect.
Description : What causes a voltage to be developed across the secondary winding of a transformer?
Last Answer : The magnetic lines generated by the current in the primary cut
Description : The electron beam in a CRT is made to sweep from left to right across the screen. What tube element causes this sweeping motion?
Last Answer : The horizontal-deflection plate.
Description : What signal causes FF2 to toggle?
Last Answer : Q output of FF 1 going LOW.
Description : What causes the specified condition to shift position?
Last Answer : The input, or clock pulse.
Description : . What causes ionization to occur in the ionosphere?
Last Answer : High energy ultraviolet light waves from the sun.
Description : what causes the initial and final pulses on the receiver output signal?
Last Answer : Leakage from the duplexer.
Description : The Doppler effect causes a change in what aspect of rf energy that strikes a moving object?
Last Answer : Frequency.
Description : What are the two common causes of transmission-line deterioration?
Last Answer : Corrosive effects of salt water and weather extremes.