Description : If the permeability of the core of a coil increases, what happens to (a) inductance and (b) true power in the circuit?
Last Answer : (a) Inductance increases; (b) true power decreases.
Description : The basic control action of a magnetic amplifier depends upon _____________. A. variations in the load capacitance B. changes in inductance C. type of core material D. construction of the core
Last Answer : Answer: B
Description : Brush sparking during commutation may be caused by ________. A. eddy currents in the armature core B. laminations in the generator field pieces C. induced current opposite to coil inductance D. coil inductance discharge occurring at commutation
Last Answer : Answer: D
Description : A saturable-core reactor operates on the principle of controlling a load winding's inductance by varying the core's _____________. A. dielectric B. permeability C. reactance D. inductance
Description : In aluminium conductors, steel core is provided to (a) compensate for skin effect (b) neutralise proximity effect (c) reduce line inductance (d) increase the tensile strength
Last Answer : (d) increase the tensile strength
Description : The greatest single cause of electrical failures is ______. A. the breakdown of insulation B. overcurrent C. high inductance D. too frequent testing
Last Answer : Answer: A
Description : If inductance increases in a series LR circuit, what happens to true power?
Last Answer : It decreases.
Description : A transmission line is said to have distributed constants of inductance, capacitance, and resistance along the line. What units of measurement are used to express these constants?
Last Answer : Inductance is expressed in micro henrys per unit length, capacitance is expressed in picofarads per unit length, and resistance is expressed in ohms per unit length.
Description : . What are two of the three physical factors that determine the values of capacitance and inductance of a transmission line?
Last Answer : (1) Type of line used, (2) dielectric in the line, and (3) length of line.
Description : If the inductance of a choke-input filter is increased, will the output ripple voltage amplitude (Er) increase or decrease?
Last Answer : Decrease.
Description : What undesirable effect is caused by the inductance of the cathode lead?
Last Answer : Degenerative feedback.
Description : Define mutual inductance.
Last Answer : Mutual inductance is the property existing between two coils so positioned that flux from one coil cuts the windings of the other coil.
Description : What happens to the value of XL as inductance decreases?
Last Answer : XL decreases.
Description : What is the basic unit of inductance and the abbreviation for this unit?
Last Answer : The henry, H.
Description : What effect does inductance have (a) on steady direct current and (b) on direct current while it is changing in amplitude?
Last Answer : a) No effect. (b) Inductance opposes any change in the amplitude of current.
Description : Is the current flow through an inductor directly proportional or inversely proportional to its inductance value?
Last Answer : Directly proportional.
Description : A Hay bridge measures inductance by comparing an inductor to what component?
Last Answer : A capacitor.
Description : Which type of optical fiber (multimode or single mode) tends to have lower loss and produces less signal distortion?
Last Answer : Single mode fiber.
Description : Which of the following iron core electromagnets creates the greatest amount of magnetic flux: w) 1,000 coils, 2 amps of current x) 250 coils, 7 amps of current y) 700 coils, 3 amps of current
Last Answer : ANSWER: Y -- 700 COILS, 3 AMPS OF CURRENT
Description : How is the effect of load flux on control flux eliminated in a saturable-core reactor?
Last Answer : use two load windings whose flux effects cancel in the core of the reactor or use two load windings on two toroidal cores so that load flux always aids control flux in one core and opposes control flux in the other core.
Description : If two coils are wound on a single iron core, what will a change in current in one coil cause in the other coil?
Last Answer : A change in inductance.
Description : What happens to the permeability of an iron core as the current increases from the operating point to a large value?
Last Answer : Permeability decreases
Description : Do small core distortions formed by arc fusion's self alignment mechanism have more of an affect on light propagating through multimode or single mode fibers?
Last Answer : Single mode fibers.
Description : Give two reasons why optical fiber manufacturers depart from the traditional circular core and cladding, low-loss glass fiber design?
Last Answer : To increase performance and reduce cost
Description : In single mode operation, the value of the normalized frequency (V) should remain near the 2.405 level. If the value of V is less than 1, do single mode fibers carry a majority of the power in the core or cladding material?
Last Answer : Cladding material.
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 : Multimode step-index fibers have relatively large core diameters and large numerical apertures. These provide what benefit?
Last Answer : Make it easier to couple light from a light-emitting diode (LED) into the fiber.
Description : In multimode step-index fibers, the majority of light propagates in the fiber core for what reason?
Last Answer : Most modes in multimode step-index fibers propagate far from cutoff.
Description : Multimode step-index fibers have a core and cladding of constant refractive index n1 and n2, respectively. Which refractive index, the core or cladding, is lower?
Last Answer : Cladding.
Description : List the standard core sizes for multimode step-index, multimode graded-index, and single mode fibers
Last Answer : Multimode step-index fibers: 50µm and 100µm. Multimode graded-index fibers: 50µm, 62.5µm, 85µm, and 100µm. Single mode fibers: between 8µm and 10µm.
Description : The refractive index of a fiber core is uniform and undergoes an abrupt change at the corecladding boundary. Is this fiber a step-index or graded-index fiber?
Last Answer : graded-index fiber?
Description : Magnetic core storage is made up of what?
Last Answer : Tiny doughnut-shaped rings made of ferrite iron.
Description : How is the core diameter defined?
Last Answer : The core diameter is defined as the diameter at which the near field intensity is 2.5 percent of the maximum intensity.
Description : Explain the difference between multimode and single mode core-cladding concentricity errors.
Last Answer : Multimode core-cladding concentricity error is the distance between the core and cladding centers expressed as a percentage of core diameter while the single mode core-cladding concentricity error is just the distance between the core and cladding centers
Description : A mode filter is a device that attenuates specific modes propagating in the core of an optical fiber. What mode propagating along single mode fibers do mode filters eliminate?
Last Answer : Second-order mode.
Description : optical launch conditions exists if the launch spot size and angular distribution are larger than that of the fiber core?
Last Answer : Overfilled.
Description : Which dispersion mechanism (material or waveguide) is a function of the size of the fiber's core relative to the wavelength of operation?
Last Answer : Waveguide dispersion.
Description : The number of modes propagated in a multimode fiber depends on core size and numerical aperture (NA). If the core size and the NA decrease, will the number of modes propagated increase or decrease?
Description : The value of the normalized frequency parameter (V) relates the core size with mode propagation. When single mode fibers propagate only the fundamental mode, what is the value of V?
Last Answer : V≤2.405.
Description : As the core and cladding modes travel along the fiber, mode coupling occurs. What is mode coupling?
Last Answer : Mode coupling is the exchange of power between two modes.
Description : A light ray incident on the optical fiber core is propagated along the fiber. Is the angle of incidence of the light ray entering the fiber larger or smaller than the acceptance angle
Last Answer : Smaller.
Description : Where are core planes used?
Last Answer : In primary storage.
Description : How are core planes formed?
Last Answer : Magnetic cores are strung together on a screen of wire.
Description : Which one of the following statements about the particular entity is true ? (a) Centromere is found in animal cells, which produces aster during cell division. (b) The gene for producing insulin is ... cell. (c) Nucleosome is formed of nucleotides. (d) DNA consists of core of eight histones.
Last Answer : (b) The gene for producing insulin is present in every body cell.
Description : When a wave is reflected from a surface, energy is transferred. When is the transfer of energy greatest?
Last Answer : When the incident wave is nearly parallel with the surface.
Description : What is the greatest danger to a transistor?
Last Answer : Heat.
Description : What is the greatest threat to a diode?
Description : Where does the greatest amount of ionospheric absorption occur in the ionosphere?
Last Answer : Where ionization density is greatest.
Description : If a transmitting antenna is placed close to the ground, how should the antenna be polarized to give the greatest signal strength?
Last Answer : Vertically polarized.
Description : What is the greatest limiting factor in a receiver’s detectable range
Last Answer : Noise.