CNS-EE4 []

CNS-EE4 Instrumentations / Energy Conversion / Others

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1. An instrument which depends on current in one or more fixed coils acting on one or more pieces of soft iron, at least one of which is movable. moving-iron instrument

2. What is that device which depends on the action of a movable permanent magnet in aligning itself in the resultant field produced either by a fixed permanent magnet and an adjacent coil or coils carrying current or by two or more current-carrying coils whose axes are displaced by a fixed angle? moving-magnet instrument

3. What ammeter is mostly used in measuring high-frequency currents? thermocouple

4. This instrument measures temperatures by electric means, especially temperatures beyond the range of mercury thermometers. pyrometer

5. This instrument refers to that one which measures the intensity of the radiation received from any portion of the sky pyranometer

6. A device used to mechanically measure the output power of a motor. dynamometer

7. An indicating instrument whose movable coils rotate between two stationary coils, usually used as wattmeter. electrodynamometer

8. Error in ohmmeter reading is due to battery aging

9. Which of the ammeter below that has no insertion error? clamp-meter

10. To prevent damage of the multirange ammeter during selection, a/an _________ should be used. Ayrton shunt

11. Voltage measurement in a high impedance circuit requires a voltmeter with high input impedance

12. If a meter with a full-scale current of 100uA is used as an ac voltmeter with half-wave rectification, its ac sensitivity is 4,500 /V

13. The zero-adjust control in an analog type ohmmeter is used to compensate for the differing internal battery voltage

14. Dynamometers are mostly used as wattmeter

15. What damping method is generally used in dynamometers? air friction


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16. Which dynamometer instrument has a uniform scale? wattmeter

17. For a dynamometer to be able to measure high current, a ___ should be used. current transformer

18. The scale of a hot wire instrument is a/an ________ function. squared

19. Moving iron instruments have a scale function that is squared

20. To increase the measuring capability of a moving-iron ac meter, a ____ should be used. different number of turns of operating coil

21. Which electrical instruments below is the most sensitive? PMMC

22. Controlling torque in PMMC. spring action

23. What damping method is used in induction type ammeters? electrostatic damping

24. Induction type instruments are mostly used as watt-hour meter

25. The force(s) that is(are) acting on the pointer of an indicating instrument as they rest on there final deflected position. (Note: damping torque is 0). controlling & deflecting torques

26. What is (are) the force(s) acting on the pointer of an indicating instrument when it is in motion? controlling, damping, and defecting torques

27. A Kelvin electrostatic voltmeter uses what method of damping? fluid friction

28. In a moving coil ammeter, a ________ is connected in series with the coil to compensate for temperature variations. swamping resistor

29. What is this measuring instrument that uses the force of repulsion between fixed and movable magnetized iron vanes, or the force between a coil and a pivoted vane-shaped piece of soft iron to move the indicating pointer? vane-type instrument

30. Its an electrostatic voltmeter in which an assembly of figure 8 shaped metal plates rotates between the plates of a stationary assembly when a voltage is applied between the assemblies. The length of the arc of rotation is proportional to the electrostatic attraction and thus, to the applied voltage. Kelvin voltmeter


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31. What is that instrument used for measuring the strength and direction of magnetic fields? magnetometer

32. What do you call of that instrument used for measuring reactive power vars? either varmeter or reactive volt-ampere meter

33. This is a method of using a Wheatstone bridge to determine the distance from the test point to a fault in telephone or telegraph line or cable. Varley loop

34. This refers to a four-arm ac bridge used for measuring inductance against a standard capacitance. Maxwell bridge

35. Refers to an ac bridge for measuring the inductance and Q of an inductor in terms of resistance, frequency and a standard capacitance. Hay bridge

36. This is a special bridge for measuring very low resistance (0.1 or less). The arrangement of the bridge reduces the effects of contact resistance which causes significant error when such low resistances are connected to conventional resistance bridges. Kelvin double bridge

37. A type of four-arm capacitance bridge in which the unknown capacitance is compared with a standard capacitance. This bridge is frequently employed testing electrolytic capacitors, to which a dc polarizing voltage is applied during the measurement. What is this bridge? Schering bridge

38. What do you call of that frequency-sensitive bridge in which two adjacent arms are resistances and the other two arms are RC combinations? Wein bridge

39. When the capacitors of a Wein bridge are replaced by inductors, the bridge becomes Wein inductance bridge

40. A simplified version of the Wheatstone bridge wherein, two of the ratio arms are replaced by a 100 cm long Manganin of uniform cross-sections and provided with a slider. slide-wire bridge

41. Electrical machine that converts ac voltage to dc voltage, or vice versa. rotary converter

42. Electrical machine that changes ac voltage at one frequency to another ac voltage at another frequency. frequency converter

43. A Synchronous type ac-motor, uses a dc generator to supply dc excitation to the rotating field

44. In a compound generator, which field winding usually, has a lower resistance? series field winding


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45. Which winding in a dc-compound generator that is relatively made of fine wires? shunt field winding

46. What is the primary reason why carbon brushes are preferred over copper brushes in dc motors? they product less arcing

47. To minimize arcing during starting of dc motors, a resistance should be added to limit the current in the ____ armature winding

48. Motors whose speed can be easily controlled. dc motors

49. When a dc motor has no load, what will happen to the back emf? becomes maximum

50. When can we get a maximum mechanical power from a dc motor? Eb = 0.5V

51. One cause why the shaft torque is less than the developed armature torque of a dc motor. friction loss

52. Considered as a variable speed motor series

53. What is the most common method used in varying the sped of a dc motor? by varying the field strength

54. In choosing a motor for a particular application, what characteristic you should consider? speed-torque

55. A motor whose speed increases as the load is increased. differentially compounded

56. Factor(s) that affect iron losses in a dc motor. flux & fied are correct

57. One advantage of a cumulatively compounded motor is that it does not run widely at light loads, this feature is due to shunt winding

58. In applications where an almost constant speed is required, a ______ motor is a good choice. dc shunt

59. In applications where a high torque is needed during starting, a ______ motor is preferred. dc series

60. In applications where sudden heavy loads happen for short duration, a ______ motor is the best choice. cumulatively compounded


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61. In motors of the same rating, which has the least starting torque? dc shunt

62. Factor(s) that affect friction and winding loses in dc motors. speed

63. In dc motors, power loss is contributed greatly by copper loss

64. When a motor is overloaded, it will usually overheat

65. Which motor that produces the highest increase in torque considering the same increase in current? dc series

66. When an armature opens in dc motor, it may cause intermittent sparking

67. Why do motors take large current during starting? theres still a low back emf

68. The law which pertains, for any dielectric reflector, the relationship in which the reflective index is equal to the tangent of the polarizing angle. Brewsters angle

69. A law that states the current in a thermoionic diode varies directly with the three-halves power of anode voltage and inversely with the square of the distance between the electrodes, providing operating conditions are such that the current is limited only by the spacecharge. Childs law

70. The logarithm of the decay constant of an alpha emitter is linearly related to the logarithm of the range of the alpha particles emitted by it is called _____. Geiger-Nuttal law

71. The law that processing power of a computer is proportional to the square of its cost. Groshs law

72. The law which states an electric motor develops maximum power when Ei = 2Ebk, where Ei is the applied voltage an dEbk is the back-emf. Jacobs law

73. The law which refers to the strength of the magnetic field at a given point, due to an element of a current-carrying conductor, is directly proportional to the strength of the current and the projected length of the element and inversely proportional to the square of the distance of the element from the point in question. Laplaces law

74. The law which concerns to a property of mutual inductances. For a given orientation and environment for two inductors, the value of the mutual inductance does not change, regardless of the magnitude, frequency, or phase of the currents in the coils. That is, mutual inductance is subject only to the physical environment surrounding the coils. Neumans law


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75. The law that sparkling potential between two parallel place electrodes in a gas I a function of the product of the gas density and the distance between the electrodes. either Paschens rule or Paschens law is right

76. The rule that hysteresis loss in a magnetic material varies directly in proportion with the cube of the magnetic induction. Rayleighs law

77. The thermal-radiation law that shows the total emissive power of ablackbody to be proportional to the fourth power of the absolute temperature of the body. Stefan-Boltzmann law

78. The wavelength of luminescence excited by radiation is always greater than that of the exciting radiation. Stokes law

79. It is a law expressing the relationship nbetween a stimulus and the physiological reaction ir produces: The sensation is proportional to the logarithm of the stimulus Weber-Fechner law

80. The law indicating that the wavelength of maximum radiation of a blackbody is inversely proportional to the absolute temperature. either Wiens first law or Wiens displacement law

81. The law showing that the emissive power of a black body is proportional to the fifth power of absolute temperature is known as either Wiens radiation law or Wiens second law

82. It is an empirical law for the spectral distribution of energy radiated from a black body at a specified temperatre. Wiens third law

83. An electromagnetic wave will take a path that involves the least travel time when propagating between two points. Fermats principle

84. The rule that states, during transitions of orbital electrons from higher to lower energy states (accompanied by the emission of the photons), changes in the inner quantum number may not only e by a factor of 0 r +/- 1. J rule

85. This is an extension of the two-fluid model of superconductivity, in which it is assumed that superfluid electrons behave as if the only force acting on them arises from the applied electric fields, and that the curl of the superfluid current vanishes in the absence of a magnetic field. London superconductivity theory

86. A formula for the overall transmittance of a signal flow graph in terms of transmittances of various paths in the graph. Masons theorem

87. This applied to a nonradiative transition of an tom from an excited energy state to a lower energy state, accompanied by the emission of an electron Auger effect


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88. Refers to the selective absorption of electromagnetic waves by a dielectric, due to molecular dipoles Dobye effect

89. The rotation induced in a freely suspended ferromagnetic object when magnetization of the object is reversed. Einstein-de Has effect

90. The random variations in the output current of an electron tube that has an oxide-coated cathode, caused by random changes in cathode emission. flicker effect

91. What do you call of the momentary illumination produced when an electric field is applied to a phosphor previously excited by ultraviolet radiation? Gudden-Pohl effect

92. The ability of ultraviolet radiation to discharge a negatively charged body in a vacuum. Hallwachs effect

93. The phenomenon whereby current in a gas changes as the result of irradiation by light is called Joshi effect

94. The variation (caused by the earths magnetic field) of the strength of cosmic rays arriving at different longitudes on the surface of the earth is known as longitude effect

95. This is the effect when the magnetization of a helically wound, ferromagnetic wire fluctuates, the tendency for a potential difference to occur. Mateucci effect

96. _______ refers to the scattering of monochromatic light (light of a single wavelength) when passed through a transparent substance. Raman effect

97. This is the ability of an electric current to destroy superconductivity by the magnetic field that it generates, without raising the cryogenic temperature. Silsbee effect

98. Electric polarization of a dielectric material being moved in a magnetic field. Wilson effect

99. What is the two-terminal semi-conductor device which resembles the behavior of a neuron and allows machines to duplicate some of the neurological phenomena observed in the human body? neuristor

100. What gadget that electronically aids the blind which has a camera that scan printed matter and a device forms corresponding raised letters which can be read with the fingertips? optacon

101. What do you call of a monostable pentode circuit that generates sharp pulses at an adjustable and accurately timed interval after receipt of a triggering signal? phantastron


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102. What instrument is used to measure the intensity of radiation, such as by determining the amount of fluorescence produced by that radiation? actinometer

103. _________ referred to a visual sensation experienced by a human subject during the passage of current through the eye. phosphene

104. It is a pattern that consists of pairs of white an dark parallel lines, obtained when an electron beam is scattered (diffracted) by a crystalline solid. The pattern gives information on the structure of the crystal. Kikuchi lines

105. An operational amplifier with double feedback limiters that drive a high-speed relay (1-2 milliseconds) is an analog computer, usually involved in controlled programming. bang-bang circuit

106. The arrangement of connecting wires in a circuit to prevent undesirable coupling and feedback. dress

107. What is that device used in biotelemetry for monitoring physiologic activity of an animal, such as pH values of stomach acid? radio pill

108. Refers to noise produced by erratic jumps of bias current between two levels at random intervals in operational amplifiers and either semiconductor devices. popcorn noise

109. A conductor in which two oscillating circuits have the same resonant frequency is called systony

110. Refers to triode electron tube having an anode that can be moved or vibrated by an externally supplied force. vibrotron

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