CUSAT CAT 2017 Question Paper Chemical Engineering

CHEMICAL ENGINEERING
(Final)

1. In a combustion process at steady state ,1 mole of carbon and 1 mole of oxygen is fed
to the system and 1 mole of carbon dioxide is obtained per unit time. The
accumulation in this process is

(A) 12 (B) 32
(C) 0 (D) 44

2. In a test ,20kg of propane was burnt with 40kg of air to produce 44kg of CO2 and
12 kg CO.What was the percent excess air?

(A) 2.27 (B) 28
(C) 13.79 (D) 2.8

3. Calculate the molality of 1 litre solution of 93% sulphuric acid (weight /volume)

(A) 0.91 (B) 10.43
(C) 9.30 (D) None of the above

4. Weight of 56 litres of ammonia at N.T.P. is __________ gram.

(A) 2.5 (B) 8600
(C) 42.5 (D) 4. 56

5. A gas at 0°C is cooled at constant pressure until its volume becomes half the original
volume. The temperature of the gas at this state will be

(A) – 273°C (B) – 136.5°K
(C) – 136.5°C (D) 0°K

6. Number of gram moles of solute dissolved in 1 kg of solvent is called its

(A) normality (B) molality
(C) molarity (D) formality

7. The value of gas constant ‘R’ is __________ kcal/kg.mole.°C.

(A) 2.79 (B) 1.987
(C) 3.99 (D) None of the above

8. The vapor pressures of benzene and toluene are 3 and 4/3 atmospheres respectively. A
liquid feed of 0.4 moles of benzene and 0.6 moles of toluene is vapourised. Assuming
that the products are in equilibrium, the vapor phase mole fraction of benzene is

(A) 0.8 (B) 0.6
(C) 0.2 (D) 0.4

2

9. 1 torr is equal to __________ mm Hg column.

(A) 1000 (B) 1
(C) 10 (D) 100

10. Which of the following ratios defines the recycle ratio in a chemical process?

(A) Recycle stream/fresh feed stream
(B) Recycle stream/gross feed stream
(C) Gross feed stream/recycle feed stream
(D) None of the above

11. What is the total pressure exerted by a mixture of 0.45 kg mole of benzene, 0.44 kg
mole of toluene and 0.23 kg mole of o-xylene at 100°C, if their vapor pressures at
100°C are 1340, 560 and 210 mmHg respectively ?

(A) 801.5 (B) 780.5
(C) 756.2 (D) 880.5

12. An azeotropic solution of two liquids has boiling point lower than either of them,
when it

(A) is unsaturated
(B) is saturated
(C) shows negative deviation from Raoult's law
(D) shows positive deviation from Raoult's law

13. Sometimes, in chemical processes, a part of the outlet stream is rejected as waste in
order to keep the impurity level in the system within limits. This phenomenon is
termed as the

(A) bypassing (B) recycling
(C) purging (D) recirculation

14. A vapor whose partial pressure is less than its equilibrium vapor pressure is called a
__________ vapour.

(A) superheated (B) saturated
(C) supersaturated (D) None of the above

15. A gas occupies a volume of 283c.c at 10°C. If it is heated to 20°C at constant
pressure, the new volume of the gas will be __________ c.c.

(A) 566 (B) 283
(C) 141.5 (D) 293

16. Brix is a unit for

(A) viscosity (B) specific gravity
(C) solubility (D) Pressure

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17. The maximum adiabatic flame temperature of fuels in air is __________ the
maximum flame temperature in pure oxygen.

(A) lower than (B) same as
(C) not related to (D) higher than

18. For water evaporating into usaturated air under adiabatic conditions and at constant
pressure, the __________ remains constant throughout the period of vaporisation.

(A) wet bulb temperature (B) dry bulb temperature
(C) relative saturation (D) humidity

19. A butane isomerisation process produces 70 kmole/hr of pure isobutane. A purge
stream removed continuously, contains 85% n-butane and 15% impurity (mole%).
The feed stream is n-butane containing 1% impurity (mole%). The flow rate of the
purge stream will be

(A) 5 kmole/hr (B) 4 kmole/hr
(C) 3 kmole/hr (D) 6 kmole/hr

20. The equilibrium value of the mole fraction of the gas dissolved in a liquid is directly
proportional to the partial pressure of that gas above the liquid surface”. This
statement pertaining to the solubility of gases in liquid is the __________ law.

(A) Henry's (B) Amgat's
(C) Raoult's (D) None of the above

21. The ratio of the actual mesh dimension of any screen to that of the next smaller screen
in the Taylor series is

(A) 2 (B) 2
(C) 102 (D) 1/ 2

22. Mesh number is number of openings per

(A) square inch of screen surface
(B) square cm of screen surface
(C) linear inch of screen surface
(D) linear centimeter of screen surface

23. ____________ law is applicable to fine grinding.

(A) Kicks law (B) Rittingers law
(C) Bonds law (D) Newtons law

24. A material which passes the 100mesh screen but was retained on 150 mesh screen can
be represented as

(A) – 100+150 (B) +100-150
(C) either (A) or (B) (D) None of the above

4

25. For settling in the stoke’s range ,the value of Reynold’s number is

(A) 2<Rep<200 (B) 200<Rep<500
(C) 500<Rep<2100 (D) 0<Rep<2

26. Kynch Theory is applicable for the design of

(A) Ball Mill
(B) Continuous thickener
(C) Distillation column
(D) Packed Bed

27. Which of the following is not categorised as a “mechanical operation”?

(A) Size enlargement (B) Filtration
(C) Agitation (D) Humidification

28. Two particles are called to be equal settling, if they are having the same.

(A) size
(B) terminal velocities in the same fluid & in the same field of force.
(C) specific gravity
(D) None of the above

29. Diatomaceous earth is a/an

(A) explosive (B) filter aid
(C) filter medium (D) catalyst

30. For a non-spherical particle, the sphericity

(A) has the dimension of length.
(B) is always less than 1.
(C) is the ratio of volume of a sphere having the same surface area as the
particle to the actual volume of the particle.
(D) is defined as the ratio of surface area of a sphere having the same
volume as the particle to the actual surface area of the particle.

31. Froth floatation is the most suitable for treating

(A) sulphide ores (B) quartzite
(C) iron ores (D) None of the above

32. The main size reduction operation in ultrafine grinders is

(A) compression (B) attrition
(C) impact (D) cutting

33. Trommels separate a mixture of particles depending on their

(A) size (B) density
(C) electrical and magnetic properties (D) wettability

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34. Shape factor for a cylinder whose length equals its diameter is

(A) 1.5 (B) 0.5
(C) 1.0 (D) 2.0

35. Equivalent diameter of a particle is the diameter of the sphere having the same

(A) ratio of surface to volume as the actual volume.
(B) ratio of volume to surface as the particle.
(C) volume as the particle.
(D) None of the above

36. The average velocity of a Newtonian fluid in a straight tube under viscous flow
conditions equals to

(A) the maximum velocity
(B) 2/3rd the maximum velocity
(C) 50% of the maximum velocity
(D) 1/3rd the maximum velocity

37. Wall thickness for schedule 80 pipe is

(A) same as that for schedule 40 pipe
(B) less than that for schedule 40 pipe
(C) more than that for schedule 40 pipe
(D) None of the above

38. Equivalent length of a wide open globe valve is __________ the equivalent length of
a half open globe valve of the same nominal size.

(A) greater than (B) lesser than
(C) same as (D) cannot say

39. For a rotameter as the flow rate increases, pressure drop

(A) increases (B) decreases
(C) remains constant (D) None of the above

40. The predominant fluid property associated with cavitations phenomenon is

(A) Surface tension (B) Vapor pressure
(C) Density (D) Viscosity

41. Newton’s law of viscosity ststes that the shear stress is directly proportional to the

(A) velocity (B) velocity gradient
(C) square of velocity (D) square of velocity gradient

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42. Poise is the unit of

(A) kinematic viscosity (B) dynamic viscosity
(C) pressure (D) power

43. Which of the following fluid is essentially a non-Newtonian fluid under normal
working conditions?

(A) Human blood (B) Thin lubricating oils
(C) Water (D) Air

44. The plot below corresponds to

(A) pseudo plastic fluid (B) real fluid
(C) bingham plastic (D) None of the above.

45. Gauge pressure at a point is equal to

(A) absolute pressure minus absolute zero pressure
(B) absolute pressure minus atmospheric pressure
(C) absolute zero pressure plus absolute pressure
(D) absolute zero pressure plus atmospheric pressure

46. Laminar flow of a Newtonion fluid ceases to exist, when the Reynolds number exceeds

(A) 3000 (B) 4000
(C) 2100 (D) 1500

47. The net positive suction head (NPSH) of a centrifugal pump is defined as the sum of
the velocity head and the pressure head at the

(A) suction
(B) discharge minus vapor pressure of the liquid at the discharge
temperature
(C) discharge
(D) suction minus vapor pressure of the liquid at suction temperature

48. Which of the following denotes the effect of compressibility in fluid flow?

(A) Mach number (B) Weber number
(C) Euler number (D) Reynolds number

49. Power loss in an orificemeter is __________ that in a venturimeter.

(A) same as (B) more than
(C) data insufficient, cannot be predicted (D) less than

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50. At high Reynolds number

(A) viscous forces predominate.
(B) inertial forces control and viscous forces are unimportant.
(C) inertial forces are unimportant and viscous forces control.
(D) None of the above

51. For a particle settling in water at its terminal settling velocity, which of the following
is true?

(A) Weight = buoyancy + drag (B) Buoyancy = weight + drag
(C) Drag = buoyancy + weight (D) Drag = weight

52. Very small pressure difference (< 5 mm water coloumn) can be most conveniently
measured by a/an __________ manometer.

(A) inclined tube water (B) U-tube water
(C) U-tube mercury (D) inclined tube mercury

53. Priming is needed in a __________ pump.

(A) diaphragm (B) centrifugal
(C) reciprocating (D) gear

54. Where does the maximum stress occur in case of laminar flow of incompressible fluid
in a closed conduit of diameter ‘d’?

(A) At d/8 from the wall (B) At the wall
(C) At d/4 from the wall (D) At the centre

55. Boundary layer separation is caused by the

(A) reduction of pressure to vapour pressure
(B) boundary layer thickness reducing to zero
(C) adverse pressure gradient
(D) reduction of pressure gradient to zero

56. When a small quantity of water evaporates into large quantity of unsaturated air, the
steady-state temperature attained is referred to as

(A) Dew point (B) Bubble point
(C) Wet-bulb temperature (D) Dry-bulb temperature

8

57. The maximum heat loss from a heated pipe occurs when the thickness of thermal
insulation is

(A) less than critical radius (B) equal to critical radius
(C) more than critical radius (D) Both (B) and (C)

58. A cold fluid is heated from 100ºC to 150ºC by steam at 200ºC. The LMTD in
counter flow is

(A) equal to the LMTD in parallel flow
(B) greater than the LMTD in parallel flow
(C) lower than the LMTD in parallel flow
(D) None of the above

59. Typically dropwise condensation occurs on cold surfaces which are

(A) smooth and clean (B) polished
(C) slightly rough and dirty (D) made of only specific materials

60. Film boiling is not usually desired in commercial equipment because

(A) it is very difficult to maintain
(B) it is not economical
(C) it is possible only in certain situations
(D) heat transfer rate is low

61. A preferred heat exchanger for gas-gas service is

(A) multi pass shell and tube (B) double pipe
(C) plate type (D) finned tube

62. For concentrating fruit juice, the recommended evaporator to be used is

(A) falling film evaporator (B) short tube vertical evaporator
(C) long tube vertical evaporator (D) agitated film evaporator

63. The cooling effect in a cooling tower can be speeded up by

(A) increasing the area of exposed wet surface
(B) decreasing the air velocity
(C) increasing the barometric pressure
(D) increasing the humidity of air

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64. In a cooling tower water is cooled from 95ºC to 80ºC by exposure to air with a wet
bulb temperature of 70ºC. The approach would be

(A) 15 º C (B) 10 º C
(C) 25 º C (D) None of the above

65. In a heat exchanger with steam outside the tubes, a liquid gets heated to 45°C, when
its flow velocity in the tubes is 2 m/s. If the flow velocity is reduced to 1 m/s, other
things remaining the same, the temperature of the exit liquid will be

(A) equal to 45°C
(B) initially decreases and remains constant thereafter
(C) less than 45°C
(D) more than 45°C

66. Function of baffles on the shell side of a heat exchanger is to

(A) decrease pressure drop (B) reduce scale deposit
(C) hold the tubes in position (D) create turbulence

67. The heat required (in kJ, up to 1 digit after the decimal point) to raise
the temperature of 1 mole of a solid material from 100°C to 1000°C is __________ .
The specific heat of the material (in J/mol-K) is expressed as CP = 20 + 0.005T,
whereT is in K. Assume no phase change.

(A) 14 kJ (B) 21.703kJ
(C) 19kJ (D) 12 kJ

68. In the Figure below showing the temperature profile , which of the following
relationship is correct. k1 and k2 are the thermal conductivities of Material 1 and
Material 2 respectively.

(A) k2  0 (B) k2  k2
(C) k2  k2 (D) k2  k2

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69. The ratio of kinematic viscosity to thermal diffusivity is known as

(A) Stanton Number (B) Mach number
(C) Nusselt Number (D) Prandtl number

70. When Biot number approached towards zero, then

(A) no surface resistance (B) high surface resistance
(C) no conductive resistance (D) None of the above

71. According to Stefan Boltzmann’s law, the emissive power of a black body is
proportional to

(A) T3/2 (B) T
(C) T4 (D) T3

72. The shell and tube heat exchanger shown in the figure below is a

(A) 2-4 shell and tube heat exchanger
(B) 4-2 shell and tube heat exchanger
(C) 2-2 shell and tube heat exchanger
(D) 4 -4 shell and tube heat exchanger

73. Which one of the following heat exchanger is used for evaporating viscous or heat
sensitive material under high vacuum?

(A) Plate and frame exchanger (B) Scraped surface heat exchanger
(C) Shell and tube heat exchanger (D) Finned tube heat exchanger

74. For strong solutions , the boiling point elevation is best found by empirical rule
known as

(A) Lambert rule (B) Duhring rule
(C) Kirchoff’s rule (D) Fourier’s rule

75. The LMTD correction factor (FT) is to be applied for

(A) counter flow exchanger (B) co-current flow exchanger
(C) cross flow exchanger (D) All of the above

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76. In a heat exchanger shell, with tube size and pitch remaining same

(A) more number of tubes can be accommodated in triangular pitch
arrangement.
(B) more number of tubes can be accommodated in square pitch
arrangement.
(C) equal number of tubes can be accommodated in both the cases
(D) cannot say

77. In a packed tower, the gas velocity must be about

(A) 0.9 times the flooding velocity (B) 0.5 times the flooding velocity
(C) 0.3 times the flooding velocity (D) 0.2 times the flooding velocity

78. For gas liquid contact the pressure drop is the least in the following equipment

(A) bubble cap tower (B) wetted wall tower
(C) perforated tray tower (D) grid tray tower

79. Langmuir equation is used in

(A) absorption (B) distillation
(C) adsorption (D) extraction

80. Which of the following methods for the design of distillation column assume constant
molal vaporization and overflow?

(A) Ponchon Savarit method (B) Mc Cabe Thiele method
(C) Ellis method (D) Enthalpy concentration method

81. The ratio of flux to concentration gradient is known as

(A) thermal diffusivity (B) eddy diffusivity
(C) mass transfer coefficient (D) volumetric diffusivity

82. Channeling is most severe in

(A) stacked packings
(B) dumped packings of crushed solids
(C) dumped packings of regular units
(D) any one of the above

83. Cox chart is used to find

(A) vapour pressure (B) viscosity
(C) specific gravity (D) diffusivity

84. In an azeotropic mixture, the equilibrium liquid composition is

(A) more than vapor composition (B) same as vapor composition
(C) less than vapor composition (D) independent of pressure

12

85. For a binary mixture at constant temperature ,with the increase of total pressure ,the
relative volatility

(A) decreases (B) increases
(C) remains constant (D) None of the above

86. If q is the moles of liquid flow per unit mole of feed in stripping section of a
distillation column, then which one of the following is true when the feed is in the
form of partially vapour and partially liquid.

(A) q > 1 (B) q < 1
(C) 0 < q < 1 (D) q = 1

87. Extraction utilizes differences in the

(A) relative volatilities of their components
(B) vapour pressure of their components
(C) solubilities of their components
(D) boiling point of their components

88. For a ternary mixture in extraction , a pure component can be represented by

(A) sides of equilateral triangular coordinates
(B) apex of an equilateral triangular coordinates
(C) a point inside the binodal curve in the equilateral triangle
(D) a point outside the binodal curve in the equilateral triangle

89. Drying operation under vacuum is used to

(A) reduce drying temperature
(B) increase drying temperature
(C) maintain drying at the same temperature as in the case of atmospheric
pressure
(D) None of the above

90. Which one of the following dryer is used for the drying of highly heat sensitive
materials?

(A) Spray dryer (B) Tray dryer
(C) Screen conveyer dryer (D) Screw conveyor dryer

91. In the formation of a crystal the driving potential is

(A) super saturation (B) saturation
(C) nucleation (D) None of the above

92. Shanks system is used for

(A) size reduction (B) counter current leaching
(C) counter current absorption (D) adsorption

13

93. Rayleigh’s equation is applicable for

(A) continuous fractionation (B) continuous absorption
(C) simple distillation (D) continuous extraction

94. Phenomenon of liquid passing through the perforations in the tray column is called

(A) flooding (B) loading
(C) coning (D) weeping

95. A spherical storage vessel is quarter–filled with toluene. The diameter of the vent at
the top of the vessel is 1/20th of the diameter of the vessel. Under the steady state
condition, the diffusive flux of toluene is maximum at

(A) the surface of the liquid
(B) the mid-plane of the vessel
(C) the vent
(D) a distance 20 times the diameter of the vent away from the vent

96. Diffusivity of solute gas A in a gaseous mixture is
(where T is the temperature)

(A) Proportional to T ½ (B) Proportional to T
(C) Proportional to T 3/2 (D) Independent of T

97. For a ternary mixture in extraction, a pure component can be represented by

(A) sides of equilateral triangular coordinates
(B) apex of an equilateral triangular coordinates
(C) a point inside the binodal curve in the equilateral triangle
(D) a point outside the binodal curve in the equilateral triangle

98. Drying operation under vacuum is used to

(A) reduce drying temperature
(B) increase drying temperature
(C) maintain drying at the same temperature as in the case of atmospheric
pressure
(D) None of the above

99. The riser in bubble cap trays conduct the flow of

(A) liquid (B) vapour
(C) both liquid and vapour (D) None of the above

100. An ideal plug flow reactor has

(A) uniform mixing (B) axial dispersion
(C) flat velocity profile (D) None of the above

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101. For any given duty and for all positive reaction orders, the size of mixed reactor is

(A) higher than plug flow reactor (B) smaller than plug flow reactor
(C) same as plug flow reactor (D) cannot say

102. For an increase in pressure in gas reactions, when the number of moles decreases
conversion

(A) decreases (B) increases
(C) unaffected (D) cannot say

103. The response curve for a step input signal from a reactor is called

(A) E-curve (B) C-curve
(C) F-curve (D) I-curve

104. In a zero order reaction, the rate of chemical reaction

(A) increases with the increase of concentration of reactants
(B) decreases with the increase of concentration of reactants
(C) is independent of the concentration of reactants
(D) None of the above

105. For a gas phase reaction at 298 K, the rate is reported as = 3.20 , /ℎ
The unit of rate constant is

(A) atm.h‒1 (B) atm‒1h‒1
(C) atm‒2h‒1 (D) atm‒3h‒1

106. For a chemical reaction,

the rate of formation of product is 0.4 mole/(litre.h).The rate of disappearance of A
must be equal to

(A) 0.4 mole//(litre.h) (B) 0.6 moles /(litre.h)
(C) 0.2moles /(litre.h) (D) None of the above

107. For a reaction

The experimental data suggests that rate=k[ ][ ]. The molecularity and order of
reaction for this reaction is

(A) 3 and 2 respectively (B) 2 and 3 respectively
(C) 3 and 3 respectively (D) 2 and 2 respectively

15

108. In a chemical reaction, the time required to reduce the concentration of reactant from
1 mole /litre to 0.5 mole/litre, is same as that required to reduce it from 50 moles/litre
to 25 mole/litre in the same volume. Then the reaction is of

(A) Zero order (B) first order
(C) second order (D) third order

109. Which one of the following reaction will be favoured by low pressure?

(A) +3 ↔2 (B) 2 + ↔2
(C) 2 + ↔2 (D) ↔2

110. With the increase in temperature the equilibrium conversion of a reversible
endothermic reaction ↔

(A) decreases (B) increases
(C) remains unaffected (D) cannot say

111. A catalyst increases the rate of a reaction, because it

(A) increases the activation energy of the reactants
(B) decreases the activation energy of the reactants
(C) brings together the reactant molecules
(D) increases the temperature

112. For mixed flow systems, the Dispersion number

(A) Tends to infinity (B) tends to zero
(C) tends to 1 (D) None of the above

113. A first order reaction requires two equal sized CSTR. The conversion is

(A) more when they are connected in series
(B) less when they are connected in series
(C) same whether they are connected in series or in parallel
(D) more when they are connected in parallel

114. The most unsuitable reactor for carrying out reactions in which high reactant
concentration favours high yields is

(A) plug flow reactor (B) series of CSTR
(C) PFR in series (D) backmix reactor

115. For every 10°C rise in temperature, the rate of chemical reaction doubles. When the
temperature is increased from 30 to 70°C, the rate of reaction increases __________
times.

(A) 12 (B) 8
(C) 16 (D) 32

16

116. __________ is the response curve for a step input signal from a reactor.

(A) I-curve (B) C-curve
(C) S-curve (D) None of the above

117. A reversible liquid phase endothermic reaction is to be carried out in a plug flow
reactor. For minimum reactor volume, it should be operated such that the temperature
along the length

(A) decreases
(B) increases
(C) first increases and then decreases.
(D) is at the highest allowable temperature throughout.

118. In an exothermic chemical reaction, the reactants compared to the products have

(A) higher temperature (B) more energy
(C) same energy (D) less energy

119. ‘N’ plug flow reactors in series with a total volume ‘V’ gives the same conversion as
a single plug flow reactor of volume ‘V’ for __________ order reactions.

(A) second (B) three
(C) first (D) any

120. Pick out the wrong statement.

(A) The vessel dispersion number (D/UL) for plug flow and mixed flow
approaches zero and infinity respectively.
(B) Space time in a flow reactor is a measure of its capacity and is equal to
the residence time when the density of reaction mixture is constant.
(C) In an ideal tubular flow reactor, mixing takes place in radial direction
and there is no mixing in logitudinal direction.
(D) Mixed reactor is always smaller than the plug flow reactor for all
positive reaction orders for a particular duty

121. Which of the following will favour the reverse reaction in a chemical equilibrium
reaction?

(A) Removal of at least one of the products at regular interval
(B) Increasing the concentration of one of the reactants
(C) Increasing the concentration of one or more of the products
(D) None of the above

122. The ratio of volume of mixed reactor to the volume of P.F.R. (for identical flow rate,
feed composition and conversion) for zero order reaction is

(A) ∞ (B) >1
(C) 1 (D) 0

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123. Quick opening valves are generally of the type of

(A) needle valve (B) globe valve
(C) diaphragm valve (D) gate valve

124. For measuring the temperature of a furnace which is the most suitable instrument

(A) thermocouple (B) optical pyrometer
(C) bimetallic thermometer (D) resistance thermometer

125. In process control it is desirable to anticipate the effect of large load changes and
reduce the maximum error; a possible control action to achieve this is

(A) proportional (B) integral
(C) derivative (D) PI control

126. When ζ =0,the nature of step response is

(A) underdamped (B) critically damped
(C) overdamped (D) undamped

127. The band width of an on-off controller is

(A) one (B) 100
(C) zero (D) infinite

128. Rheometer is used to measure

(A) density (B) viscosity
(C) molecular diffusivity (D) velocity

129. In an underdamped second order response, the value of decay ratio is equal to

(A) overshoot (B) overshoot 2
(C) overshoot‒2 (D) overshoot‒1

130. A special case of proportional control is on-off control, when its gain Kc is

(A) zero (B) infinity
(C) 1 (D) None of the above

131. Servo problem is encountered when there is a change in

(A) set point (B) load variable
(C) manipulated variable (D) None of the above

1
132. Consider a system with G ( s)  2
. The percentage overshoot for this system
s  s 1
for a step change is

(A) 63.5% (B) 16.6%
(C) 32 % (D) 83%

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133. Consider a pure capacitance system with P-controller in a closed loop. If there is a
unit step change in set point for the system, the offset is

(A) zero (B) one
(C) infinity (D) no sufficient information to determine

134. Air to open type control valve

(A) opens when air pressure fails (B) closes when air pressure fails
(C) Both of the above (D) None of the above

135. A P controller gives an offset. We would like to have zero offset. You recommend

(A) adding integral action (B) adding derivative action
(C) use large KC (D) set Kc=0

136. A gain margin of less than one means

(A) unstable system (B) stable system
(C) critically stable system (D) underdamped system

137. Thermistor, which has high temperature co-efficient of resistivity, is used as the
sensing element in resistance thermometer. It is a/an

(A) liquid semi-conductor (B) insulator
(C) solid semi-conductor (D) conductor

138. Flapper nozzle is used in a/an __________ controller.

(A) electronic (B) pneumatic
(C) hydraulic (D) None of the above

139. Typical specifications for design stipulates the gain margin and phase margin to be
respectively

(A) > 1.7 and > 30° (B) < 1.7 and > 30°
(C) < 1.7 and < 30° (D) > 1.7 and < 30°

140. Response of a system to a sinusoidal input is called __________ response.

(A) unit step (B) impluse
(C) frequency (D) None of the above

141. The operation of a rotameter is based on

(A) pressure drop across a nozzle (B) pressure at a stagnation point
(C) rotation of a turbine (D) variable flow area

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142. The closed loop pole of a stable second order system could be

(A) complex conjugate with positive real parts
(B) both real and negative
(C) both real and positive
(D) one real positive and the other real negative

143. The Laplace transform of is

(A) s2f(s) –s f(0)–f l(0) (B) s f(s) –s f(0)–f l(0)
(C) sf(s) – f(0) (D) s2 f l(s) –f(0)

144. Which of the following second order systems are equivalent to two first order systems
in series?

1 1
(A) G(s)  2
(B) G ( s)  2
s  2s  2 s  1.9 s  0.7
1 1
(C) G(s)  2 (D) G (s)  2
s 5 s s2

145. If the absolute temperature of an ideal gas is doubled and pressure is reduced to one
half, the volume of gas will

(A) increase two fold (B) increase four fold
(C) decrease two fold (D) remains unchanged

146. For a reversible adiabatic process ΔS is

(A) < 0 (B) > 0
(C) = 0 (D) None of the above

147. The expansion of a gas into vacuum is

(A) reversible process (B) irreversible process
(C) Both of the above (D) None of the above

148. Five moles of an ideal gas are compressed isothermally at 400ºK from 1 atm to 5atm.
Calculate the free energy change for the process.

(A) – 5116.7 cal (B) 5116.7cal
(C) 21409.39cal (D) – 21409.39cal

149. Pore diffusion resistance in a catalyst is considered negligible if Theile modulus is

(A) > 1 (B) < 1
(C) < 0.5 (D) > 0.5

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150. An adiabatic system can exchange energy with its surroundings

(A) only in the form of work
(B) either in the form of heat or work
(C) in the form of only heat
(D) both in the form of heat and work

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