12. A signal established as a standard of comparison for a feed back control system by virtue of its

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Bridget Lane
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1 INSTRUMENTATION AND CONTROL SYSTEMS 2 MID ONLINE BITS 1. "A function of the controlled output, which is compared with the reference input to obtain the actuating signal" is called as :->Primary feed back signal 2. "Any finite number of blocks that are series connected my be algebraically combined by multiplying their transfer function". This statement is called as :->Blocks in cascades 3. "Applying the force to some elastic member and then measuring the resulting deflection to measure the applied force" is used in :->Proving ring 4. "The quality or condition characterizing a process whose value is held constant by controller or is changed according to certain law" is called as :->Controlled variable 5. A bellow system is used to measure temperature. The input heat is q. Bellow expansion is x. Then the transfer function is :->x / q 6. A control system that has no connection between the output and the input is known as :->Open - loop system 7. A high gauge factor leads to a :->Large change in resistance for a s mall change in strain input 8. A metallic toothed roter having 60 teeth was mounted on a shaft whose speed was to be determined. The pulses produced in the inductive type magnetic pickup were registered to be 3600 per second. Estimate the speed. :->3600 rpm 9. A pendulum scale is a :->Mechanical transducer 10. A Prony brake dynamometer measures :->Engine brake power 11. A signal established as a standard of comparison for a feed back control system by virtue of its relation to command is called as :->Set point 12. A signal established as a standard of comparison for a feed back control system by virtue of its relation to command is called as :->Reference input 13. A strain gauge is used to measure strain of 1 micro-strain. Its initial resistance is 120 ohms and change in resistance is Ω. What is the gauge factor :->2 14. A strain gauge with a gauge factor 2 is sued to measure a strain of 1 micro strain. The corresponding resistance shown by the strain gauge is ohm. Then the initial resistance is equal to :->120 ohms 15. A strain gauge with initial resistance of 120 Ω and gauge factor of 2 is used to measure strain. When the resistance change shown by the instrument is Ω. What is the strain. :->1 micro strain 16. A unity feed back system is :->Closed loop feed back system where the transfer function in feed back loop is unity 17. Absolute humidity refers to :->The amount of water vapor actually present in the air 18. Acceleration pickups will be made to have :->High undampe d natural frequency 19. Actuating signal is :->An algebra sum of the reference input and the primary feed back 20. An algebraic sum of the reference input and the primary feed back signal is called as :->Actuating signal 21. An input that is established or varied by some means external to and independent o f the feed back control system is called as :->Command

2 22. An instrument used to measure angular velocity of a shaft either by registering the number of rotations during the period of contact or by indicating directly the number of rotations per minute is c alled as :- >Tachometer 23. Any control system that operates on time basis of :->Open-loop control system 24. Bakelite gauges used for 2000 C will be fixed to components with :->Phenol resin cement 25. Chose the wrong statement :->The Prony brake is much steadier in operation than the rope brake dynamo meter 26. Command means :->An input that is established or varied by some means external to and indepe ndent of the feed back control system 27. Control systems is :->An assembly of devices and components connected or related, so as to command, direct or regulate itself or another system 28. Controlled medium means :->The process material in the controlled system or flowing through it in which the variable is to be controlled. 29. Controlled variable means :->The quality or condition characterizing a process whose value is held constant by controller or is changed according to certain low. 30. Cradled source or cradled sink are the words associated with :->Torque measure ment 31. Dew point temperature refers to :->Tempe rature whe re the water vapor in the air starts condensing 32. Digital accelerometer is a :->Deflection type device 33. Direct output one can get from recording psychro meter is :->Dry and wet bulb temperature 34. Direct output one can get from sling psychro meter is :->Dry and wet bulb temperature 35. Dry bulb temperature refers to :->Te mperature of air - wate r vapor mixture as indicated by a thermometer whose bulb is exposed to the mixture 36. Dual gauge is :->A gauge which is built with two different mate rials and inbuilt te mperature compensation 37. Dummy strain gauges :->Are bonded to separate unstrained component and suffer resistance change due to temperature only 38. Electric cradled dynamo meter is a type of :->Driving dynamo meter 39. For a electrical rheostat y is the input displacement and q0 is the output. The transfer function = :- > 40. For a power limit of 25,000 HP which dynamometer you will suggest :->Water vertex dynamometer 41. For a speed limit of 10,000 rpm which dynamometer you will suggest :->Wate r vertex dynamometer 42. For a spring mass dash pot system, input is x(t1 ), output is f(t), k is spring stiffness, c is dash point coefficient 'm' is the mass the transfer function is :-> 43. For a strain gauge the gauge factor is 2 and the resistance is 120 ohms. If the strain sensed is 2 micro strains. The change is resistance = :->ohms 44. For a temperature control system 'q' in is heat input, θ is temperature to be to maintained in the system is the ambient temperature, q is the leakage to the surroundings, R is the resistance and C is the capacitance, then the input and output relations are written up :-> 45. For a temperature range of C, on can use a :->Duco gauges

3 46. For a water turbine input is the flow of water (q) flowing through the turbine. The output of the turbine speed is w. The transfer function is :->w / q 47. For many metals the resistivity :->Will not change with strain 48. For most metallic strain gauges, most of the resistance change comes from :->Change in length and area 49. For semiconductor gauges the change in resistance is due to :->Change in resistivity 50. Froudes absorption dynamometer is a :->Vortex type hydraulic dynamometers 51. Gauge using carrier material made with paper, impregnated with nitro cellulos e cement and bonded with cellulose constituents are called as :->Duco gauges 52. Gravimetric hygro meter is used to :->To calibrate other humidity measuring devices 53. Greater lineaxity and lack of hysteresis is possible with :->Servo accelerometer 54. Hydraulic dynamometer :->Use fluid friction for dissipating the energy 55. Hygrometer is :->Instrument used to measure relative humidity 56. In a differential angular potential mater one arm is set at reference inclination θ1. The other arm inclination is θ0. If 'e' is the output voltage then the transfer function is :-> 57. In n type semi - conductor gauges resistance decrease with :->Tensile Strain 58. In P type semi - conductor gauges resistance increases with :->Tensile Strain 59. In Poisson's arrangement (one gauge perpendicular to other) the bridge output when compared t o quarter bridge output is :->(1 + µ ) times 60. In the seismic mass type vibrometer the desirable damping ratio is approximately :->65 % 61. In the seismic mass type vibrometer the influence of damping ratio on seismic mass output for high values of w/wn :->Negligible 62. In the sesimic mass type vibrometer, when the frequency ratio is considerably greater than one, the complitude ratio nears to :->Near to unity 63. Instrument used to help is measuring humidity is :->Psychoro meter 64.is the change in output voltage of (Vs is excitation voltage, F is gauge factor, E is strain) :->Quarter bridge 65.is the change in output voltage of (Vs is excitation voltage, F is gauge factor, E is strain) :->Half bridge 66. Load limiting torque is :->Max possible torque which a dynamometer can exert 67. Manipulated variable means :->The quality on condition that is varied as a function of the actuating signal so as to change the value of controlled variable. 68. Mark the Transmission dynamometer :->Flash light torsion dynamometer 69. Mechanical strain gauges can measure :->Static and quasi static strains 70. Mechanical strain gauges cannot be employed for :->Dynamic strains 71. Mechanical torsion meter measures :->Twist on the shaft 72. Negative feed back will _ the error :->Reduce 73. Null - balance accelerometer have :->Feed back signal 74. On a strain gauge torsional meter :->Four gauges, two gauges in torsion, two gauges in compressor 75. Out of the following gauges which one is having large mass :->Unbonded 76. Out of the following instrument which can be used as both vibrometer and accelerometer after doing some modifications. :->Sesimic mass type 77. Out of the following instruments which can be used as both vibrometer and accelerometer after doing some modifications. :->Seismic mass type

4 78. Out of the following instruments which employs the concept of resonance as the means of speed measurement :->Vibrating Reed Tachometer 79. Out of the following instruments which instrument has highest speed range :->Slipping clutch tachometer 80. Out of the following instruments which instrument has highest speed range :->Centrifugal force Tachometer 81. Out of the following instruments which occupies less space for the same power :->Hydraulic dynamo meter 82. Out of the following instruments which one is practically more valuable for general monitoring than for test work. :->Vibrating Reed Tachometer 83. Out of the following instruments, which instrument will yield information about only amplitude of vibration :- >Wedge vibrometer 84. Out of the following speed measuring instruments which one put less load on the machine whose speed is being measured :->Revolution counter 85. Out of the following vibrating measuring instrument which one will use 'resonance' as a means of measurement. :->Reed vibrometer 86. Out of the following which instrument you will recommend for high frequency response in acceleration measurement :->Pie zo - electric 87. Out of the following which is contact less electrical tachometer :->Photo electric Tacho meter 88. Out of the following which is contact less non electrical Tacho meter :->Vibrating reed Tacho meter 89. Out of the following which is not of the seismic mass type transducer :->Reed vibrometer 90. Out of the following which is not the part of a seismic transducers :->Reed 91. Out of the following, which one will not increase the sensitivity of wheat stone bridge in strain measurement. :->Small excitation voltage 92. Paper impregnated with phenolic resin used as a backup material for gages to be used at :->2000 C 93. Positive feed back will _ the error :->Increase 94. Power assisted steering in automobile is an example of :->Servo mechanis m 95. Primary feed back signal means :->A function of the controlled output, which is compared with the reference input to obtain the actuating signal 96. Prony brake dynamometer :->Will absorb the powe r i.e. being measured 97. Proving ring is a :->Mechanical transducer 98. Psychro meter is :->Instrume nt used to measure wet bulb and dry bulb temperature 99. Ratio between humidity of air to the humidity of saturated air is called as :->Relative humidity 100.Ratio of mass of water vapor to the mass of dry air in a given volume of air-water vapor mixture is called as :->Specific humidity 101.Reed vibrator will yield information about :->Frequency only 102.Reference input means :->A signal established as a standard of comparison for a feed back control system by virtue of its relation to command 103.Relative humidity refers to :->Ratio of humidity of air with the humidity of saturated air 104.Relative output displacement of a sesimic mass instrument is a not function of :->Mass 105.Set point means :->A signal established as a standard of comparison for a feed back control system by virtue of its relation to command 106.Simply turning the accelerometer upside down is :->Constant acceleration method of calibration

5 107.Strain gauge accelerometer is a type of :->Seismic mass type accelerometer 108.Stroboscope is used in :->Torsion measure ment 109.Stroboscopic method of vibration measurement will yield the information about :->Frequency only 110.Tachometer are used to measure :->Angular velocity 111.Temperature at which the water vapor in the air starts condensing is called as :->Dew point temperature 112.Temperature of air - water vapor mixture as indicated by a thermometer w hose bulb is e xposed to the mixture :->Dry bulb temperature 113.Temperature of air - water vapor mixture as registered by a thermometer w hose bulb is covered by a wick maintained continuously wet is called as :->Wet bulb tempe rature 114.The advantage of capacitive and inductance transducers have :->Retaining calibration 115.The amount of water vapor actually present in the air is called as :->Absolute humidity 116.The average speed measurements are given by :->Drag cup tachometer 117.The bridge constant (sensitivity) of full bridge arrangement when two strain gauges of adjacent limbs suffer positive strain and the two remaining gauges suffer negative sign (when compared to quarter bridge) :- >Quadruple 118.The bridge constant (sensitivity) of half bridge arrangement where two strain gauge s suffer equal and opposite strains is (when compared with quarter bridge) :->Doubled 119.The calibration standard for hygrometer is :->Gravimetric hygrometer 120.The capacitive and inductive transducers cannot be used in some applications due to :->Large mass and size 121.The change in output voltage dvo for half bridge is Where Vs is the excitation voltage F is the gauge factor E is the strain :->VsF E / The change in output voltage for full bridge is _ Where Vs is the excitation voltage F is the gauge factor E is the strain :->VsF E 123.The change in output voltage for quarter bridge is Where Vs is the excitation voltage F is the gauge factor E is the strain :->VsF E / The desired condition of the controlled variable is :->Reference 125.The direct output from dynamometer is :->Torque 126.The drag cup Tacho meter principle is based on :->Torque generated by eddy current 127.The electric switch is an example of :->Open-loop control system 128.The name of the element, which determines the difference between the reference point and measured variable is. :->Controlled 129.The out put of the ballast circuit when compared with quarter bridge configuration of wheat stone bridge :->Equal 130.The output of a standard strain gauge load cell is :-> 131.The output of Dunmore type absorption hygro meter is :->Relative humidity 132.The particular variable to be regulated is known as :->Controlled 133.The phase angle Ø of sesimic mass instrument output is a not function of :->Mass

6 134.The phase shift in vibrometer seismic mass type is :->Linear shift with frequency 135.The prime objective of any control system is to maintain the _ variable at the reference set point :->Controlled 136.The principle behind multi- level platform scale in force measurement is :->Balance the force against a known gravitational force on a standard mass 137.The principle behind the hydraulic load cell in force measurement is :->Translating the force to a fluid pressure and the measuring the resulting pressure 138.The principle behind the proving ring is :->Applying the force to some elastic me mber and then measuring the resulting deflection. 139.The process material in the controlled system or flowing through it in which the variable is to be controlled is called as :->Controlled medium 140.The quality or condition that is varied as a function of the actuating signal so as to change the value of controlled variable. :->Manipulated variable 141.The resistance change in a metallic strain gauge is a factor of :->Change in area and length 142.The seismic mass instrument measures :->The relative displacement between mass housing 143.The seismic mass transducer for the measurement of acceleration and vibra tion is a :->Second order instrument 144.The sensitivity of wire - wounded strain gauge will increase with increase in :->Gauge factor 145.The speed of a sealed compressor units can be measured by :->Vibrating reed Tachometer 146.The stroboscopic method of speed measurement has the advantage that :->There is no need of any physical contact between the instrument and the rotating shaft 147.The Tacho generator principle is based on :->Tacho generator 148.The Tacho meter principle is based on :->Faraday's law 149.The Tacho meter which operates based on torque generated from eddy currents is :->Drag cup type 150.The width of the wedge at the point where the image over lap while using the vibrating edge for vibration measurement is :->Double the amplitude of motion 152.'Time between the pulses' will be used to measure torque in the following way of torque measurement. :->Electrical 153.To avoid moisture absorption the following type of cement will be selected :->non - hygroscopic 154.To have a large change in resistance for a small changing in strains, one has to use :->A strain gauge with a large gauge factor 155.To increase the range of use, input frequencies of a sesimic mass type vibrometer should be :- >Above the instrume nt undamped natural frequency 156.Traffic light at a junction is an example of :->Open - loop control system 157.Transfer function is :->Output / input 158.Translating the force to a fluid pressure and then measuring the resulting pressure to me asure the applied force is used in :->Hydraulic load cell 159.Transmission dynamometers :->Will measure powe r whe n it is being transferred from one place to other place 160.Unlimited values of static accelerations can be fed to accelerometers during calibration by :- >Centrifuge method 161.Vibrating wedge is used to measure :->Amplitude of vibration 162.Vibration pickups will be made to have :->Low undampe d natural frequency 163.Vibrometer out put is proportional to :->Displace ment

7 164.VsF E is the change in output voltage of (Vs is excitation voltage, F is gauge factor, E is strain) :- >Full bridge 165.When a disk is rotating at 900 rpm, the frequency of light where image of a single mark on the disk appears as double and stationery is :->1800 rpm 166.When a disk is rotating at 900 rpm. The frequency of light where image of a s ingle mark on the disk appears single stationery mark is :->450 rpm 167.When one strain gauge is used the bridge output is k. When 'n' no of strain gauges is used then the output voltage is :->n k 168.When the shafts are inaccessible, then what type of Tachometer will be used to measure speeds. :- >Vibrating reed Tachometer 169.When the wet bulb and dry bulb temperature are known from the psychometric charts we ca n find out :->Specific humidity 170.When using a wheat stone bridge circuit for measuring strain, the accurate technique is initial resistance is equal to :->Balanced condition (Null) 171.Which bonding material will be used to bond strain gauges at C :->The rmoset 172.Which bonding material will be used to bond strain gauges at 800 C :->The rmo plastic 173.Which bonding material will be used to bond strain gauges at greater than C :->Special ceramic 174.Which instrument uses the principle of "change of electrical resistance with change in humidity" as the humidity measuring technique. :->Dunmore hygro meter 175.Which of the following cannot be the controlled variable of a servomechanism :->Torque 176.Which of the following cannot be used for dynamic straining :->Balanced condition (Null) 177.Which of the following gauge will exhibit freedom form faulty insulation :->Unbonded type 178.Which of the following gauges are less suit to measure bending strains :->Unbonded type 179.Which of the following gauges have high gauge factor :->Semi - conductor gauges 180.Which of the following gauges have poor heat dissipation :->Unbonded type 181.Which of the following gauges have very little or no transverse sensitively :->Unbonded type 182.Which of the following gauges will exhibit less creep hystersis :->Unbonded type 184.Which of the following is a characteristic of closed- loop system :->The error signal activates the control element to minimize the error and bring the system output to the desired value 185.Which of the following is a desired characteristic for strain gauge bonding materials. :->High dielectric strength 186.Which of the following is a desired characteristic for strain gauge bonding materials. :->Non - hygroscopic 187.Which of the following is a multi lever balancing type force measuring instrument :->Pendulum scale 188.Which of the following is a null type instrument :->Servo accelerometer 189.Which of the following is disadvantage with ballast circuit :->Providing temperature compensation is difficult 190.Which of the following is not a method of temperature compensation in strain gauge :->Duco gauge 191.Which of the following is the characteristic of open - loop system :->For the given set-input, the re may be big vibration of the controlled variable 192.Which of the following material has a negative gauge factor, when used as strain gauge :->Nickel 193.Which of the following materials will be used for strain gauges tha t can be used for static strain measurement :->Advance

8 194.Which of the following materials will be used for that can be used for high temperature applications :- >Iridium platinum 195.Which of the following materials will be used for that can be used for dynamic strain measurements :- >Nichrome 196.Which of the following strain gauge are brittle and not suitable for measurement of large strains :- >Semi - conductor gauges 197.Which of the gauge has inherent temperature compensatio n :->Dual gauge 198.Which type of gauge you will recommend, for curved bonded surface :->Foil gauges 199.Which type of the following gauge the gauge factor is not constant but varies with strain and temperature :->Se mi - conductor gauges 200.While measuring pure torsion, the strain gauges are bonded to the shaft :->At 450 to the axis of rotation 201.Windage torque is :->Lowest possible powe r or torque required to turn the rotating parts and to over come the bearing friction and othe r Windage losses

INSTITUTE OF AERONAUTICAL ENGINEERING (Autonomous) Dundigal, Hyderabad

INSTITUTE OF AERONAUTICAL ENGINEERING (Autonomous) Dundigal, Hyderabad -500 043 MECHANICAL ENGINEERING TUTORIAL QUESTION BANK Name : INSTRUMENTATION AND CONTROL SYSTEMS Code : A70343 Class : IV B. Tech