0% 0 Process Control and Instrumentation Quiz 5 1 / 50 The second order system with the transfer function 4/(s2 + 2s + 4) has a damping ratio of _____? 4 0.5 1 2 2 / 50 Time constant is the ___________? Same as dead time Time taken by the controlled variable to reach 63.2% of its full change Time required by the measured variable to reach 63.2% of its ultimate change Same as transportation lag 3 / 50 Thermistor, which has high temperature co-efficient of resistivity, is used as the sensing element in resistance thermometer. It is a/an ? Insulator Solid semi-conductor Liquid semi-conductor Conductor 4 / 50 The root locus method, a pole of a transfer function G(s) is the value of s for which G(s) approaches _____? -1 1 ? 0 5 / 50 The offset introduced by proportional controller with gain Kc in response of first order system can be reduced by ______? Introducing integral control Introducing derivative control None of the above Reducing value of Kc 6 / 50 Thermocouple is suitable for measuring__________? Very high temperatures only Both high and low temperatures Liquid temperatures only Very low temperatures only 7 / 50 The transfer function for an ideal proportional plus reset controller (reset time T) is________? Kc/[1 + (s/T)] Kc/(1 + TS) Kc[1 + (1/TS)] Kc(1 + TS) 8 / 50 Thermal conductivity measurement is used for the determination of_________? Composition of an alloy CO2 percentage in the flue gas O2 percentage in the flue gas Specific gravity of petrofuels 9 / 50 What is the Laplace transform of impulse input having magnitude ?X? ? X 1/X 1 X2 10 / 50 The transfer function of a first order system is_______? 1/Ts 1/(Ts + 1) s/(Ts + 1) None of these 11 / 50 The unit step response of the transfer function (2s ? 1)/[(3s + 1) (4s + 1)] reaches its final steady state asymptotically after ______? A monotonic increase Initially increasing and then decreasing Increasing decreasing and then increasing A monotonic decrease 12 / 50 Thermal well made of ______ gives the fastest speed of response, while measuring temperature by thermocouples? Steel Inconel Vycor (a glass) Nichrome 13 / 50 The thermal emf-temperature relationship of most thermocouples is__________? Exponential Square root Linear Parabolic 14 / 50 Transfer function of transportation lag is_____? None of these eTS e-TS 1/(Ts + 1) 15 / 50 Water is flowing through a series of four tanks and getting heated as shown in figure. It is desired to design a cascade control scheme for controlling the temperature of water leaving the tank 4 as there is a disturbance in the temperature of a second stream entering the tank 2. Select the best place to take the secondary measurement for the second loop? Tank 2 Tank 4 Tank 3 Tank 1 16 / 50 The open loop transfer function of a control system is KR/(1 + TS). This represents _______? Dead time system A second order system A first order time lag A first order system 17 / 50 The time constant of a first order process with resistance R and capacitance C is___________? 1/RC R ? C RC R + C 18 / 50 What is the dynamic error in a critically damped second order instrument for a ramp input (At) ? 2 AT ?(AT) 1.5 AT 0.5 AT 19 / 50 To increase the speed of response of a pressure spring liquid or gas expansion thermometer, the clearance space between the thermometer bulb and the thermal well should not be filled with _________? Air A metal powder or graphite Oil Mercury 20 / 50 Use of I-control along with P-control facilitates ? Reduction of stability time Elimination of offset Reduction of offset None of these 21 / 50 Thermistors which have a very high temperature co-efficient of resistivity belong to the class of solid called_________? Dielectrics Insulators Conductors Semi conductors 22 / 50 The transfer function for a P-D controller is_________? Kc(1 +1/?D s) Kc(1+?D s) Kc ?D s Kc/?D s 23 / 50 The term analogous to the electrical current in a thermal system is the__________? Temperature difference None of these Heat content in the system Heat flow rate 24 / 50 Water is entering a storage tank at a temperature T0 and flow rate Q0 and leaving at a flow rate Q and temperature T. There are negligible heat losses in the tank. The area of cross-section of the tank is A0. The model that describes the dynamic variation of temperature of water in the tank with time is given as_________? Q0(T0 ? T) = Ac . h (dT/dt) Q0T0 ? QT = Ac . h (dT/dt) Q(T0 ? T) = Ac . (dTH/dt) Q(T0 ? T) = Ac . h (dT/dt) 25 / 50 Vapour actuated pressure spring thermometer does not require ambient temperature compensation. Ambient temperature compensation is provided in gas or liquid expansion pressure spring thermometer by___________? Making the volume of thermometer bulb as large as conveniently possible Reducing the volume of the capillary to a minimum Reducing the volume of the receiving element to a minimum All A , B & C. 26 / 50 Thermal conductivity based continuous flue gas analyser makes use of varying thermal conductivity of the constituents of flue gases. Which of the following constituents of flue gases has the maximum thermal conductivity ? CO2 CO N2 O2 27 / 50 The transfer function for a PID controller is (where, ? i is the integral (reset) time and ?D is the derivative time.) ? Kc(1 + ?is + ?D ). s Kc[1 + (1/?is) + ?D . s) Kc(1 + ?is + (1/?D . s) None of these 28 / 50 The time taken for a radioactive element to reduce to 50% of its original weight is ______ years, if its half life period is 12 years? 18 6 24 36 29 / 50 The temperature of tempering oil baths maintained at 400?C during heat treatment of steel is measured by a/an ______ thermocouple? None of these Iron-constantan Chromel-alumel Platinum-platinum/rhodium 30 / 50 Thermal conductivity measurement com-prises the working principle of a__________? Spectrometer Polarimeter CO2 analyser Chromatograph 31 / 50 Thermistors are made of___________? Nickel-chromium alloys Metal oxides Iron-copper alloys Ultra pure metals 32 / 50 Very low pressure is expressed in microns (?), which is equal to _____ mm of Hg column (absolute) at 0?C? 0.001 0.0001 0.1 0.01 33 / 50 Volumetric expansion is the working principle of the _______ thermometers? Mercury in glass Vapor pressure Bimetallic Constant volume gas 34 / 50 Thermistors are used in _____ devices? Temperature measuring Voltage measuring Both B. & C. Temperature compensating 35 / 50 Thermocouple in a thermal well behaves as a true _________? Second order system (underdamped) Multiple first order system First order system Second order system (overdamped) 36 / 50 Thermal wells used in temperature measurements should have ___________? Very thick walls Low emissivity High transmissivity of radiation Polished surface 37 / 50 Thermal wells are used in the temperature measurement to______? Guard against corrosive and oxidising action on thermocouple materials Reduce measuring lag Increase the sensitivity Increase the fidelity 38 / 50 Turbine flow meters are suitable for__________? Very limited flow ranges Cryogenic flow measurements Both B. and C. Aerospace and in air borne applications 39 / 50 The pressure sensing element of elastic type pressure gauge is never made in the form of a__________? Strip Bellow Diaphragm Bourdon tube 40 / 50 The term analogous to voltage in a single tank system is the________? Liquid volume in the tank Level of liquid Flow rate Heat content of the system 41 / 50 The root locus plot of the roots of the characteristics equation of a closed loop system having the open loop transfer function K (s + 1)/[2 (2s + 1) (3s + 1)] will have a definite number of loci for variation of K from 0 to ?. The number of loci is________? 2 3 4 1 42 / 50 The operation of a Rotameter is based on _________? Rotation of a turbine Pressure at a stagnation point Pressure drop across a nozzle Variable flow area 43 / 50 The unit of ?time constant? of a system is the same as that of_____? None of these Velocity Time (Time)-1 44 / 50 The time constant of a unity gain, first order plus time delay process is 5 min. If the phase lag at a frequency of 0.2 rad/min is 60?, then the dead time (in minutes) is_________? ?/12 ?/3 5?/12 ?/6 45 / 50 The response of two tanks of same size and resistance in series is ___________? Over damped Under damped None of the above Critically damped 46 / 50 The unit step response of the transfer function 1/(s2 + 2s + 3) _________? Is unstable Has a non-zero slope at the origin Is overdamped Has a damped oscillatory characteristics 47 / 50 The open loop transfer function of a process is K [{(s + 1) (s + 4)}/{(s + 2) (s + 3)}]. In the root locus diagram, the poles will be at _____? -1, -4 2, 3 1, 4 -2, -3 48 / 50 The transfer function of a second order system is _______? 1/(T2s2 + 2Ts + 1) 1/(T2s2 + 2?T + 1) None of these 1/(T2s2 + 2?Ts + 1) 49 / 50 Thermal conductivity cell is the primary element of a/an ______ analyser? Oxygen Carbon monoxide Carbon dioxide Sulphur dioxide 50 / 50 Thermodynamic Celsius scale of temperature measurement is_________? Defined on the basis of melting point of ice and condensation temperature of water vapor Defined on the basis of melting point of ice and evaporation temperature of water vapor Both B. and C. Having an interval of 100? between ice point to steam point Provide Your Information Your score is The average score is 0% LinkedIn Facebook Twitter 0% Restart quiz Send feedback Share on facebook Facebook Share on twitter Twitter Share on whatsapp WhatsApp PrevProcess Control and Instrumentation Quiz 3 Process Control and Instrumentation Quiz 6Next
