chemical engineering Mcqs
4701. Nickel percentage in invar which is an iron-nickel alloy, and is used as a thermocouple material is __________________?
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A. 68

B. 12

C. 54

D. 36
4702. The unit step response of the transfer function 1/(s2 + 2s + 3) _______________________?
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A. Is overdamped

B. Has a damped oscillatory characteristics

C. Has a non-zero slope at the origin

D. Is unstable

4703. Which of the following is never used as an element of industrial resistance thermometer ?
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A. Nickel

B. Lead

C. 30% iron + 70% nickel

D. Copper

4704. Conversion formula for converting amplitude ratio (AR) into decibels is ________________?
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A. Decibel = 20 loge (AR)0.5

B. Decibel = 20 log10 (AR)0.5

C. Decibel = 20 loge (AR)

D. Decibel = 20 log10 (AR)
4705. Which of the systems having the following transfer function is stable ?
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A. 1/(S2 + 2)

B. 1/(S2 + 2S + 2)

C. exp (-20 S)/(S2 + 2S 1)

D. 1/(S2 2S + 3)

4706. Working principle of radiation pyrometer is based on the ________________?
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A. Stefan-Boltzmann law

B. Kirchoffs law

C. Wiens law

D. Seebeck effect

4707. A metal oxide is reduced by heating it in a stream of hydrogen. After complete reduction, it is found that 3.15 gm of the oxide has yielded 1.05 gm of the metal. It may be inferred that the ____________________?
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A. Equivalent weight of the metal is 4

B. Equivalent weight of the metal is 8

C. Atomic weight of the metal is 4

D. Atomic weight of the metal is 2

4708. The initial value (t = 0) of the unit step response of the transfer function [(s + 1)/(2s + 1)] is__________________?
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A.

B. 2

C. 1

D. 0

4709. Refluxing of part of the distillate in a fractionating column is a recycling operation, aimed primarily at_______________?
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A. Heat conservation

B. Yield enhancement

C. Product enrichment

D. None of these

4710. Which of the following relates the emf. generated in a single homogeneous wire to the temperature difference ?
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A. Peltier effect

B. Seebeck effect

C. None of these

D. Thomson effect
4711. A sinusoidal variation in the input passing through a linear first order system _________________?
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A. Becomes less oscillatory (frequency decreases)

B. Gets amplified (magnitude increases)

C. Becomes more oscillatory (frequency increases)

D. Gets attenuated (magnitude decreases)
4712. The unit of Cp in S.I. units is___________________?
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A. W/m.K

B. W/m2.K

C. J/m3. K

D. J/kg.K
4713. The characteristic equation for the control system with a closed loop transfer function G1/1 + G2 is given by 1 + G2 = 0. The characteristic equation for the control system_________________?
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A. All A , B & C.

B. Is the same for set point or load changes

C. Depends only upon the open loop transfer function

D. Determines its stability

4714. A bypass stream in a chemical process is useful, because it___________________?
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A. Facilitates better control of the process

B. Improves the conversion

C. Increases the yield of products

D. None of these

4715. Pressure of 0.01 psi (absolute) can be measured by ______________ gauge?
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A. None of these

B. Ionisation

C. Mcleod

D. Pirani

4716. A mercury barometer measures the _____________ pressure?
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A. Absolute

B. Vacuum

C. Gauge

D. Atmospheric
4717. An aneroid barometer measures the _____________ pressure?
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A. Atmospheric

B. Vacuum

C. Absolute

D. Gage

4718. Thermal wells used in temperature measurements should have __________________?
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A. Low emissivity

B. Very thick walls

C. Polished surface

D. High transmissivity of radiation
4719. Response of a system to a sinusoidal input is called _____________ response?
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A. Unit step

B. Impulse

C. None of these

D. Frequency
4720. A system with a double pole at the origin is unstable since the corresponding term in the time domain________________?
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A. Is a constant

B. Grows linearly with time

C. Decays linearly with time

D. Grows exponentially with time

4721. Which of the following is not a variable area flow meter ?
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A. Magnetic flow meter

B. Piston type meter

C. Orifice and tapered plug meter

D. Rotameter

4722. Which of the following is not a unit of pressure ?
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A. Torr

B. m2

C. Parsec

D. Ata, bar or Pascal

4723. Thermal conductivity measurement is used for the determination of________________?
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A. Specific gravity of petrofuels

B. O2 percentage in the flue gas

C. CO2 percentage in the flue gas

D. Composition of an alloy

4724. Which of the following is not the triple point of water ?
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A. 273K

B. 32F

C. 32R

D. 492R

4725. The frequency response of a first order system, has a phase shift with lower and upper bounds given by________________?
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A. -?/2, 0

B. ?, ?/2

C. 0, ?/2

D. -?/2, ?/2

4726. Emf developed by a thermocouple while measuring a temperature of 400C is 22 mV. The type of thermocouple used is ___________________?
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A. Platinum-platinum + rhodium

B. Iron-constantan

C. Chromel-alumel

D. Platinum-rhodium

4727. Configuration of Bourdon spring tube is never made of _____________ shape?
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A. Helical

B. Spiral

C. Circular

D. Semi-circular

4728. Which of the following thermocouples is the most suitable for measuring a temperature of about 1600C in an oxidizing atmosphere ?
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A. Iron-constantan

B. Chromel-alumel

C. Copper-constantan

D. Platinum-platinum + rhodium
4729. Gas chromatography is used for the measurement of ________________?
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A. Pressure

B. Concentration

C. Temperature

D. Flow rate

4730. If the absolute temperature of an ideal gas is tripled and simultaneously the pressure is reduced to one third; then the volume of gas will _______________?
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A. Increase nine fold

B. Increase three fold

C. Remain unaltered

D. Decrease three fold

4731. Isotonic solutions must have the same__________________?
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A. Molar concentration

B. Normality

C. Critical temperature

D. Viscosity

4732. The weight fraction of methanol in an aqueous solution is 0.64. The mole fraction of methanol XM satisfies________________?
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A. 0.5 < XM < 0.64

B. XM < 0.5

C. XM ? 0.64

D. XM = 0.5

4733. Emf developed by a thermocouple, while measuring a temperature of 600C is about 5.5 mV. The type of thermocouple used is_______________?
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A. Chromel-alumel

B. Platinum-platinum + rhodium

C. Either A., B. or C.

D. Iron-constantan

4734. Which of the following thermocouples will give the highest output for the same value of hot and cold junction temperature ?
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A. All will give the same output

B. Chromel-constantan

C. Iron-constantan

D. Platinum-platinum + rhodium

4735. Which of the following is not a second order instrument ?
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A. Mercury in glass thermometer with covering

B. Pressure gauge with one bellow, two tubes and a tank

C. None of these

D. Bare mercury in glass thermometer
4736. Bode diagram are generated from output response of the system subjected to which of the following input ?
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A. Ramp

B. Step

C. Sinusoidal

D. Impulse

4737. Which of following error integral is considered as the best criterion in controller settings ?
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A. ?0 ? |e| dt

B. None of these

C. ?0 ? |e2| dt

D. ?0 ? e2 dt
4738. What is the Laplace transform of impulse input having magnitude X? ?
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A. X

B. 1

C. X2

D. 1/X

4739. For a given mass of a gas at constant temperature, if the volume V becomes three times, then the pressure P will become______________?
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A. 3P

B. 9P2

C. P/3

D. 9P

4740. The transfer function of a second order system is _____________________?
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A. 1/(T2s2 + 2?Ts + 1)

B. 1/(T2s2 + 2Ts + 1)

C. 1/(T2s2 + 2?T + 1)

D. None of these

4741. What is the overall transfer function (C/R) of the following block diagram if G = G1. G2. G3 and H = H1.H2 ?
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A. 1/(1 + GH)

B. G/(1 + GH)

C. H/(1 + GH)

D. G/(1 GH)

4742. Kopps rule is helpful in finding the__________________?
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A. Heat capacities of gases

B. Heat capacities of solids

C. Molal heat capacities of gases

D. Activation energy

4743. Simultaneous doubling of the absolute temperature of a gas and reduction of its pressure to half will result in _____________ in the volume of the gas?
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A. Doubling

B. 1/4th reduction

C. No change

D. Fourfold increase

4744. Which of the following is not a mechanical pressure sensing element ?
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A. Bellows

B. Bourdon tube

C. U-tube

D. Diaphragm

4745. In a feed-back control system G and H denote open loop and close loop transfer functions respectively. The output-input relationship is_____________?
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A. H/G

B. H/(1 + G)

C. G/(1 + H)

D. G/H

4746. Which of the following thermocouples can measure the maximum temperature ?
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A. Iron-constantan

B. Tungsten-molybdenum

C. Chromel-alumel

D. Platinum-rhodium

4747. Characteristic equation is the denominator of ____________ loop transfer function?
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A. Open

B. Closed

C. Both A. and B.

D. Neither A. nor B.

4748. Liquid discharge from a tank or reservoir cannot be measured by __________________?
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A. Mouthpieces

B. Orificemeter

C. Weirs

D. Notches

4749. The experimental response of the controlled variable y(t) for a step change of magnitude P in the manipulated variable x(t) is shown below: The appropriate transfer function of the process is_________________?
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A. (Q/R) e-TdS/(Q/P) (S + 1)

B. (Q/R) e-(P/Q)S/(TdS + 1)

C. (Q/P) e-TdS/(Q/R) (S + 1)

D. (Q/P) e-(Q/R)S/(TdS + 1)

4750. Relationship between absorption/evolution of heat at the thermocouple junctions and the current flow in the circuit is given by _____________ effect?
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A. Peltier

B. Thomson

C. Seebeck

D. None of these