0% 0 Process Control and Instrumentation Quiz 5 1 / 50 The transfer function of a second order system is _______? 1/(T2s2 + 2Ts + 1) 1/(T2s2 + 2?Ts + 1) 1/(T2s2 + 2?T + 1) None of these 2 / 50 Thermistors which have a very high temperature co-efficient of resistivity belong to the class of solid called_________? Conductors Dielectrics Semi conductors Insulators 3 / 50 The unit step response of the transfer function 1/(s2 + 2s + 3) _________? Is overdamped Has a damped oscillatory characteristics Is unstable Has a non-zero slope at the origin 4 / 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 All A , B & C. Reducing the volume of the capillary to a minimum Reducing the volume of the receiving element to a minimum 5 / 50 The second order system with the transfer function 4/(s2 + 2s + 4) has a damping ratio of _____? 4 0.5 1 2 6 / 50 What is the dynamic error in a critically damped second order instrument for a ramp input (At) ? ?(AT) 0.5 AT 2 AT 1.5 AT 7 / 50 The operation of a Rotameter is based on _________? Pressure drop across a nozzle Pressure at a stagnation point Variable flow area Rotation of a turbine 8 / 50 Thermal conductivity measurement com-prises the working principle of a__________? Chromatograph Polarimeter Spectrometer CO2 analyser 9 / 50 Thermal wells used in temperature measurements should have ___________? High transmissivity of radiation Very thick walls Polished surface Low emissivity 10 / 50 Thermodynamic Celsius scale of temperature measurement is_________? Defined on the basis of melting point of ice and evaporation temperature of water vapor Defined on the basis of melting point of ice and condensation temperature of water vapor Both B. and C. Having an interval of 100? between ice point to steam point 11 / 50 What is the Laplace transform of impulse input having magnitude ?X? ? X 1 X2 1/X 12 / 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) Q(T0 ? T) = Ac . (dTH/dt) Q(T0 ? T) = Ac . h (dT/dt) Q0T0 ? QT = Ac . h (dT/dt) 13 / 50 The open loop transfer function of a control system is KR/(1 + TS). This represents _______? A first order system A second order system Dead time system A first order time lag 14 / 50 The term analogous to voltage in a single tank system is the________? Heat content of the system Level of liquid Flow rate Liquid volume in the tank 15 / 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________? 1 3 2 4 16 / 50 The transfer function of a first order system is_______? 1/(Ts + 1) 1/Ts None of these s/(Ts + 1) 17 / 50 Very low pressure is expressed in microns (?), which is equal to _____ mm of Hg column (absolute) at 0?C? 0.0001 0.001 0.01 0.1 18 / 50 Thermal conductivity cell is the primary element of a/an ______ analyser? Carbon dioxide Carbon monoxide Oxygen Sulphur dioxide 19 / 50 Thermocouple is suitable for measuring__________? Both high and low temperatures Very low temperatures only Liquid temperatures only Very high temperatures only 20 / 50 Volumetric expansion is the working principle of the _______ thermometers? Constant volume gas Mercury in glass Bimetallic Vapor pressure 21 / 50 The time constant of a first order process with resistance R and capacitance C is___________? R + C 1/RC R ? C RC 22 / 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 O2 N2 CO 23 / 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? 36 24 18 6 24 / 50 Thermistors are used in _____ devices? Temperature compensating Both B. & C. Temperature measuring Voltage measuring 25 / 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_________? ?/3 ?/6 ?/12 5?/12 26 / 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 27 / 50 The unit step response of the transfer function (2s ? 1)/[(3s + 1) (4s + 1)] reaches its final steady state asymptotically after ______? Increasing decreasing and then increasing A monotonic increase Initially increasing and then decreasing A monotonic decrease 28 / 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 + (1/?D . s) None of these Kc(1 + ?is + ?D ). s Kc[1 + (1/?is) + ?D . s) 29 / 50 The temperature of tempering oil baths maintained at 400?C during heat treatment of steel is measured by a/an ______ thermocouple? Iron-constantan Platinum-platinum/rhodium Chromel-alumel None of these 30 / 50 Thermal conductivity measurement is used for the determination of_________? CO2 percentage in the flue gas O2 percentage in the flue gas Specific gravity of petrofuels Composition of an alloy 31 / 50 Thermal well made of ______ gives the fastest speed of response, while measuring temperature by thermocouples? Vycor (a glass) Nichrome Inconel Steel 32 / 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 4 Tank 2 Tank 3 Tank 1 33 / 50 The pressure sensing element of elastic type pressure gauge is never made in the form of a__________? Diaphragm Bourdon tube Strip Bellow 34 / 50 Use of I-control along with P-control facilitates ? Elimination of offset Reduction of stability time None of these Reduction of offset 35 / 50 The unit of ?time constant? of a system is the same as that of_____? None of these (Time)-1 Time Velocity 36 / 50 The response of two tanks of same size and resistance in series is ___________? Under damped None of the above Critically damped Over damped 37 / 50 Time constant is the ___________? Time taken by the controlled variable to reach 63.2% of its full change Same as dead time Same as transportation lag Time required by the measured variable to reach 63.2% of its ultimate change 38 / 50 Turbine flow meters are suitable for__________? Aerospace and in air borne applications Both B. and C. Cryogenic flow measurements Very limited flow ranges 39 / 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 _________? Mercury Air A metal powder or graphite Oil 40 / 50 The transfer function for a P-D controller is_________? Kc(1+?D s) Kc(1 +1/?D s) Kc/?D s Kc ?D s 41 / 50 Thermocouple in a thermal well behaves as a true _________? First order system Second order system (underdamped) Second order system (overdamped) Multiple first order system 42 / 50 Thermistors are made of___________? Nickel-chromium alloys Iron-copper alloys Metal oxides Ultra pure metals 43 / 50 The offset introduced by proportional controller with gain Kc in response of first order system can be reduced by ______? Reducing value of Kc None of the above Introducing integral control Introducing derivative control 44 / 50 Thermal wells are used in the temperature measurement to______? Reduce measuring lag Guard against corrosive and oxidising action on thermocouple materials Increase the sensitivity Increase the fidelity 45 / 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 Conductor Liquid semi-conductor 46 / 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 _____? -2, -3 2, 3 1, 4 -1, -4 47 / 50 The term analogous to the electrical current in a thermal system is the__________? Temperature difference Heat content in the system None of these Heat flow rate 48 / 50 The thermal emf-temperature relationship of most thermocouples is__________? Square root Linear Exponential Parabolic 49 / 50 Transfer function of transportation lag is_____? None of these eTS e-TS 1/(Ts + 1) 50 / 50 The transfer function for an ideal proportional plus reset controller (reset time T) is________? Kc(1 + TS) Kc/[1 + (s/T)] Kc/(1 + TS) Kc[1 + (1/TS)] 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
