1. If a body is at thermal equilibrium, then:

Emissivity absorptivity

Emissivity absorptivity

Emissivity absorptivity

None of the above

2. The heat transfer by conduction through a pipe is given by the relation:

<img src='./qimages/3399-2.jpg'>

3. With the help of fins, the heat transfer can be increased by about:

4 times

6 times

8 times

10 times

4. In a low speed S.I. engine, the inlet valve closes approximately:

40° after BDC

30° before BDC

10° after BDC

10° before BDC

5. The function of fuel injector is to:

Pump the fuel at high pressure

Mix diesel with air

Atmoise the fuel

Ignite the fuel

6. The function of carburettor is to:

Refining the fuel

Increase the pressure of fuel vapours

Inject petrol in cylinder

Atomise and vapourise the fuel and to mix it with air in proper ratio

7. In S.I. engine, the throttle valve of carburettor controls the quantity of:

Fuel

Air

Fuel and air mixture

Lubricating oil

8. The function of a hydraulic turbine is to convert water energy into:

Heat energy

Electrical energy

Atomic Energy

Mechanical energy

9. The specific speed of a turbine is:

Its maximum speed

Its minimum speed

Its speed at maximum output

The speed of a geometrically similar turbine that would develop one metric horse power under a head of one meter

10. The type of turbine recommended for a head of 10 meter is:

Francis turbine

Kaplan turbine

Pelton turbine

None of the above

11. The vanes of a centrifugal pump move due to:

Pressure energy of water

Kinetic energy of water

Both pressure and kinetic energy of water

Power supplied by prime mover

12. The specific speed of a centrifugal pump is given as:3

<img src='./qimages/3399-12.jpg'>

13. Which of the following compressors has highest capacity?

Reciprocating

Centrifugal

Axial flow

Fan

14. The volumetric efficiency of a reciprocating compressor is equal to:









15. The thermal efficiency of an open cycle gas turbine increases with the:

Increase in inlet temperature of atmospheric air

Decrease in inlet temperature of atmospheric air

Remain same for all temperatures of inlet air

None of the above

16. Constant volume gas turbine works on:

Joule cycle

Carnot cycle

Otto cycle

Atkinson cycle

17. The capacity of boiler is defined as:

The volume of feed water inside the shell

The volume of the steam space inside the shell

The maximum pressure at which steam can be generated

Amount of water converted into steam from 100°C to 110°C in one hour

18. The type of safety valve recommended for high pressure boiler is:

Dead weight safety valve

Lever safety valve

Spring loaded safety valve

None of the above

19. Blade efficiency of steam turbine is equal to:

<img src='./qimages/3399-19.jpg'>

20. The gas which is used as a coolant in a nuclear power plant is:

Freon

Ammonia

Helium

Chlorine

21. The function of a reflector in nuclear power plant is to:

Reflect heat

Reflect light

Reflect the escaping neutrons back into the core

None of the above

22. If the capacity of a refrigerating machine is one ton, than the rate of heat abstraction is equal to:

50 kcal/min

100 kcal/min

150 kcal/min

500 kcal/min

23. The refrigeration system works on:

Zeroth law of thermodynamics

First law of thermodynamics

Second law of thermodynamics

None of the above

24. Which of the refrigerant is more toxic? Carbon dioxide

Ammonia

Freon-12

Freon-22

25. Which of the following refrigerant is more costly?

Ammonia

Carbon dioxide

Methyl chloride

Freon-12

26. Pick up the correct statement:

The refrigerant should have high thermal conductivity and low freezing temperature

The refrigerant should have low heat transfer coefficient and high latent heat

The refrigerant should have high specific volume and high latent heat

The refrigerant should have high specific volume and low latent heat

27. Which of the following refrigerant has maximum latent heat?

Sulphur dioxide

Carbon dioxide

Ammonia

Dichloro-difloro-methane

28. A refrigerant should have the following property:

High boiling point

High latent heat

High specific heat

High specific volume

29. The necessary data required for the design of the air conditioning apparatus is/are:

Grand total heat

Dehumidified air quantity

Apparatus dew point

All of the above

30.

<img src='./qimages/3399-30.jpg'>
then momentum equation of the boundary layer can be given as follows:







A.B=C

31. For non-flow closed system the value of net energy transferred as heat and work equals change in:

Enthalpy

Entropy

Internal energy

None of the above

32. During throttling process the following holds good:

Enthalpy does not change

Entropy does not change

Internal energy does not change

Volume change is negligible

33. For an adiabatic process, the temperature and pressure are related as under:

<img src='./qimages/3399-33.jpg'>
34. An engine operates between temperature limits 900 K and T2 and another between T2 and 400 K. For both engines to be equally efficient T2 should be:

600 K

700 K

625 K

650 K

35. For a process, the value of is:

Positive

Negative

Zero

Unpredictable

36. Area under the curve of a T-S diagram represents:

Heat transfer for a reversible process

Heat transfer for an irreversible process

Heat transfer for all processes

None of the above

37. A heat engine developes 60 kW work having an efficiency of Amount of heat rejected will be:

400 kW

10 kW

40 kW

20 kW

38. In Carnot cycle, addition and rejection of heat takes place at:

Constant pressure

Constant temperature

Constant volume

Constant speed

39. For same value of compression ratio and heat input, the order of thermal efficiency of Otto, Diesel and Dual cycles will be as under:

n Otto >Diesel Dual

(b)Otto Dual Diesel

(c)Diesel Dual Otto

Dual> Diesel> Otto

40. A heat engine receives 1120 kJ of heat and rejects 840 kJ of heat while operating between two temperature limits of 560 K and 280 K. It indicates that the engine operates on the following cycle:

Reversible cycle

Irreversible cycle

Impossible cycle

Unpredictable cycle

41. Change in entropy for a natural process will always be:

Zero

Positive

Negative



42. The thermal efficiency of an ideal Otto cycle:

Increases with compression ratio

Increases with specific heat ratio

Increases with compression ratio and specific heat ratio

Increases with compression ratio but decreases with specific heat ratio

43. Critical radius of insulation for sphere is equal to:

2k.h

h 2k

2k h

k.h

44. If the ratio of emission of a body to that of a black body at a given temperature is constant for all wavelengths, the body is called:

Black body

Gray body

White body

Opaque body

45. The thickness of thermal boundary layer is equal to hydrodynamic boundary layer when Prandtl number is equal to:

0

0.1

1.0

10

46. A composite wall consists of three different materials having thermal conductivities 2K and 4K respectively. The ratio of temperature drop across different materials will be:

1

4

1

1

47. A body cools from 90°C to 70°C in 5 minutes. The time required by body for further cooling to 50°C will be:

5 minutes

Less than 5 minutes

More than 5 minutes

10 minutes

48. The value of Stanton number for value of Nusselt number 400, Reynolds number 40 and Prandtl number 20 will be:

800

200

2

0.5

49. Assuming the Sun to be a black body emitting radiation with maximum intensity at the surface temperature of the sun will be:

491.4 K

4914 K

49140 K

491.4° C

50. According to Wien's law, the wavelength corresponding to maximum energy is proportional to:

T

T

T

T

51. LMTD in case of counter flow heat exchanger as compared to parallel flow heat exchanger is:

Lower

Higher

Same

Unpredictable

52. For radiation between two large parallel plates having emissivities and the effective emissivity will be:

<img src='./qimages/3399-52.jpg'>

53. In turbulent filmwise condensation on a vertical surface, the critical value of Reynolds number recommended for use is:

2300

1800

5x105

1000

54. The intensity of solar radiation on earth is of the order of

1 kW/m2

2 kW/m2

3 kW/m2

4 kW/m2

55. Free convection heat transfer is significantly affected by:

Reynolds number

Grash of number

Prandtl number

Stanton number

56. In a counterflow heat exchanger, the hot fluid is cooled from 110°C to 80°C by a cold fluid which is heated from 30°C to 60°C. LMTD for the heat exchanger will be:

80°C

50°C

30°C

20°C

57. Fouling factor in the design of heat exchanger is used considering the fact that:

It is used when a liquid exchanges heat with gas

It is used in case of Newtonian fluids

It is used as a dimensionless factor

It is a factor of safety in design

58. Which dimensionless number has the significant role in forced convection:

Mach number

Reynold number

Prandtl number

Pecklet number

59. Air standard efficiency of an Otto cycle having compression ratio 4 and adiabatic exponent for air r =1.5 will be:

50%

75%

25%

5.0%

60. Thermal efficiency of a Carnot engine is 30%. If the engine is reversed to operate as heat pump with same operating conditions, what will be the COP of the heat pump?

0.3

1.33

2.33

3.33

61. An oil having kinematic viscosity 0.25 stokes flows through a pipe of 10cm diameter. The flow will be critical at a velocity of about:

0.5 m/s

1.5 m/s

1.8 m/s

4.6 m/s

62. Unit of kinematic viscosity is:

m2/s

N.s/m2

kg/s.m2

m/kg.s

63. Navier Stoke's equation is concerned with:

Turbulence

Viscosity

Buoyancy

Compressibility

64. When a fluid flows through a pipeline under viscous flow conditions, the ratio of velocity at the axis of the pipe to the mean velocity of flow is:

0.5

1.0

1.67

2.0

65. In a turbulent flow through a pipe, the shear stress is:

Maximum at the centre and decreases linearly towards the wall

Maximum at the centre and decreases logarithmically towards the wall

Maximum mid-way between the centre line and the wall

Maximum at the wall and decreases linearly to zero at the centre

66. At what distance from the centre of a pipe of radius does the average velocity occur in laminar flow:

r 0.33

r 0.707

r 0.50

r 0.59

67. The loss of head due to friction in a pipe of uniform diameter in which a viscous flow is taking place is given in terms of Reynolds number, Re as:

1/Re

4/Re

16/Re

64/Re

68. Hydraulic radius is equal to:

Area divided by the square of wetted perimeter

Area divided by the wetted perimeter

Wetted perimeter divided by area

Square root of area

69. An oil with specific gravity 0.85 and viscosity 3.8 poise flows in a 5cm diameter horizontal pipe at 2.0 m/s. The Reynolds number will be approximately:

224

2240

22.4

22400

70. The nominal thickness of boundary layer represents the distance from the surface to a point where:

Flow ceases to be laminar

The shear stress becomes maximum

Velocity is 99% of its asymptotic limit

None of the above

71. In a laminar boundary over a flat plate, what would be the ratio of wall shear stresses t 1 and 2 at two sections which lie at distances X1= 2 units and X2= 10 units from the leading edge of the plate:

1 2 5.0

1 (5)0.5

1 (5)0.25

1 (5)0.05

72. The height of water column corresponding to a pressure equivalent of 60 cm of mercury column will be:

816 cm

8160 cm

81.6 cm

7996.0 cm

73. Loss of head due to friction to maintain 0.05 m3/s of discharge of petrol (sp. gravity 0.7) through a steel pipe 0.2 m diameter and 1000 m long, taking coefficient of friction 0.0025 will be

0.644 m

6.44 m

64.4 m

644 m

74. If the compression ratio is increased in S.I. engine, the knocking tendency will:

Increase

Decrease

Not be affected

Cannot be predicted

75. Anti knock property of C.I. engine fuel can be improved by adding:

Tetra ethyl lead

Amylnitrate

Hexadecane

Trimethyl pentane

76. The injection pressure in diesel engine is of the order of:

30 40 bar

100 150 bar

200 300 bar

400 600 bar

77. Carbon deposit on the cylinder head of an I.C. engine tend to increase:

Clearance volume

Compression ratio

Swept volume

None of the above

78. An impulse turbine is used for:

Low head of water

High head of water

Medium head of water

High discharge

79. If the jet ratio in a Pelton turbine wheel is 18, the number of buckets will be about:

24

21

26

18

80. A low value of time constant for a thermocouple can be achieved by:

Decreasing the wire diameter

Using metals of high density and high specific heat

Increasing the heat transfer coefficient

and above

81. In order to avoid cavitation in centrifugal pumps:

The suction pressure should be high

The delivery pressure should be high

The suction pressure should be low

The delivery pressure should be low

82. Thermal efficiency of closed cycle gas turbine plant is increased by the following:

Reheating

Inter cooling

Regenerator

None of the above

83. Most of the terrestrial solar radiations (received on the earth) lie within wavelength range:

to 0.29mewm

0.29mewm to 2.5mewm

3.8mewm to 7.8mewm

102mewm to1010 mewm

84. Flat plate solar collectors are used for temperature applications above ambient of about:

20°C

50°C

100°C

1000°C

85. A Carnot refrigerator operates between 300.3K and 273K. The fraction of cooling effect required as work input is:

20%

10%

50%

Cannot be calculated

86. A Carnot refrigeration cycle has a COP of 4. The ratio of higher temperature to lower temperature will be:

2.5

2.0

1.5

1.25

87. Vapour compression cycle using R-12 gives maximum COP when:

Suction state to compressor is in wet region

Suction state to compressor is in superheat region

Suction state to compressor is dry saturated

None of the above

88. In a simple saturated vapour compression refrigeration cycle, the heat rejected in condenser is 160 kJ/kg and compressor work is 32 kJ/kg, then the COP will be:

4

5

6

None of the above

89. In aqua-ammonia and LiBr-Water absorption refrigeration system, the refrigerants are respectively:

Water and LiBr

Water and Water

Ammonia and LiBr

Ammonia and Water

90. Room sensible heat factor is defined as Room sensible heat, RLH: Room Latent heat):

RSH (RSH+RLH)

RLH (RSH+RLH)

RSH RLH

None of the above

91. The surrounding air temperature in summer is 45°C in a locality. The refrigeration temperature is 5°C. Assume 10°C temperature difference in the heat exchanger that exchanges heat with surroundings. The COP of the Carnot refrigerator under these conditions, will be:

6.95

7.95

6.56

5.56

92. In an ammonia vapour compression system, wet compression process is used instead of dry compression. The C.O.P.:

Will increase

Will decrease

Can increase or decrease

Remains unaffected

93. A regenerative liquid vapour heat exchanger is used in a vapour compression system operating on ammonia refrigerant, the COP:

Will increase

Will decrease

Can increase or decrease

Remains unaffected

94. The refrigerant C2H4 is designated as:

R 24

R 15

R 1150

R 150

95. External equalizer in thermostatic expansion valve is used so that the TEV senses the pressure of evaporator:

At the outlet

At the inlet

In the middle

At outlet as well as inlet

96. If COP of a vapour compression system is the heat rejection ratio of its condenser will be:

0.25

5.0

1.25

0.20

97. Aircraft refrigeration system is based upon:

Joule cycle

Brayton cycle

Carnot cycle (reversed)

Vapour compression cycle

98. If F is mass handled by a pump and D is refrigerant vapour distilled in a vapour absorption system, specific weak solution circulation is given by:

F/D

F D





99. The system used for cooling of supersonic aircraft is:

Simple system

Bootstrap system

Reduced ambient system

Regenerative system

100. Lewis number is given by the following relation: heat transfer coefficient, Kw is mass transfer coefficient and Cp is specific heat):

<img src='./qimages/3399-100.jpg'>

101. A sample of moist air is at a dry bulb temperature of 21°C and dew point temperature of 15°C. Specific humidity of air is 0.011 kg w.v./kg d.a. What will be the enthalpy of moist air?

59.4 kJ/kg d.a.

323.4 kJ/kg d.a.

52.5 kJ/kg d.a.

49.0 kJ/kg d.a.

102. During adiabatic saturation process of air in air washer, the water is sprinkled at a surface temperature equal to ————— of incoming DBT WBT DPT None of the above

103. When steam is injected into the incoming air, the following changes occur in the condition of air:

Temperature increases significantly but specific humidity increases negligibly.

Temperature increases negligibly but specific humidity increases appreciably.

Both temperature and sp. humidity increase appreciably.

Both temperature and sp. humidity increase negligibly.

104. In the concept of effective temperature, the relative humidity of air is considered to be:



50%

75%

100%

105. For atmospheric air, following conditions are given:DBT 35°C, DPT 23°C and barometer reads 750 mm Hg. Saturation pressure at 23°C and 35°C is 21.06 mm Hg and 42.4 mm Hg respectively. The relative humidity and partial pressure of water vapour will be:

49.7% and 21.06 mm Hg respectively

35.5% and 42.4 mm Hg respectively

35.5% and 15.06 mm Hg respectively

Impossible to calculate

106. Some qualities of C.I. engine fuels are given below. Select the quality which is not desirable:

Good ignition quality

High volatility

High viscosity

Low flash point

107. In C.I. engines, ignition delay can be reduced by:

Decreasing compression ratio

Increase in air inlet temperature

Decrease in coolant temperature

Decreasing the engine speed

108. A Pelton turbine works under a head of 405 m and runs at 400 rpm. What will be diameter of its runner? (kn 0.45):

1.93m

3.80m

2.10m

None of the above

109. A Kaplan turbine develops 3000 kW power under a head of 5m and a discharge of 75 m3/s. Determine the overall efficiency:

0.79

0.82

0.90

None of the above

110. A centrifugal pump lifts 0.013 m3/s water from a depth of 32 m. If the pump motor consumes 6 kW, what is the overall efficiency of pump. Given density of water 1000 kg/m3:

88%

75%

69%

None of the above

111. Run away speed for Francis turbine ranges:

1.8 to 1.9 times normal speed

2.5 to 3 times normal speed

3 to 3.5 times normal speed

2 to 2.2 times normal speed

112. In centrifugal compressors, pressure ratio may be increased:

By decreasing slip factor

By increasing slip factor

By making rough blades

By none of the above

113. If B is magnetic field strength, the theoretical power output of MHD generator is proportional to:

B

B2

B3

routeB

114. Absorption of energy in solar collectors can be increased to a maximum value by coating the absorber surface by:

Black paint

Lamp black

Rough black coating

Selective coating

115. On increasing the temperature of absorber plate of solar collector the efficiency of collector:

Increases

Decreases

May increase or decrease depending upon atmospheric temperature

Does not depend on absorber plate temperature

116. Solar photovoltaic cell is made up of semiconductor materials. The efficiency of conversion of solar energy into electrical energy is of the order of:



21%

70%

90%

117. The following boiler operates in supercritical range of pressure:

Benson

Babcock and Wilcox

Loeffler

Cornish

118. Pressure compounding can be done in the following type of turbines:

Impulse turbines

Reaction turbines

Both impulse and reaction turbines

None of the above

119. The first law of thermodynamics was given by:

Obert

Keenan

Joule

Newton

120. Gas A at 1 MPa, 100°C and Gas B at 5 MPa, 100°C are mixed such that final temperature after mixing remains 100°C. The process is adiabatic. The entropy of the gases after mixing:

Will increase

Will remain same

Will decrease

Cannot be calculated

121. T1 is high and T2 is low temperature of a Carnot heat engine. Which is the most efficient way to increase efficiency?

To increase T1

To decrease T2

To increase T1 and T2 both

To decrease T1 and T2 both

122. A refrigerator (COP=2.5) removes energy by heat transfer from freezer at 0°C at a rate of 9000 kJ/hr and rejects energy to the surroundings. Determine power input to the refrigerator:

614.3 kJ/hr

3600 kW

659.3 kJ/hr

1 kW

123. A machine produces 100 kJ work by consuming 100 kJ heat. This machine will be called:

PMM I

PMM II

PMM III

None of the above

124. For a steady flow system (where kinetic and potential energies are negligible), the first law of thermodynamics can be expressed as:

dQ dW dU



W deltaU

W deltaH

125. A gas turbine plant operates between 27°C, minimum temperature and 927°C maximum temperature. Calculate the cycle efficiency:

25%

50%

75%

None of the above

126. The effect of regeneration on efficiency and work output of Brayton cycle is that its:

Efficiency decreases but work output increases

Efficiency as well as work output increases

Efficiency increases but work output remains same

Efficiency remains same but work output increases

127. Which cycle consists of three processes?

Ericsson cycle

Stirling cycle

Atkinson cycle

Lenoir cycle

128. Third law of thermodynamics is:

An extension of second law

An extension of first law

An independent law of nature

An extension of zeroth law

129. A 20 cm diameter pipe of 30 km length transports oil at 0.01 m3/s. The power required to 2 3 maintain flow will be =0.1N s/m2 ,density 900kg/m3

76.32 kW

7.632 W

763.2 W

0.7632 kW

130. A small air bubble of diameter 1.0 mm rises with a steady velocity of 1.5 cm/s through an oil of specific gravity 0.9. The viscosity of oil will be:

3.24x10-3 N-s/m2

32.4x10-3 N-s/m2

32.4x10-6 N-s/m2

None of the above

131. The flow in the capillary tube is laminar because:

The capillary tube is made of glass

The surface tension and capilarity promotes laminarisation

Only inviscid liquid can flow through capillary tube

The diameter of capillary tube is very small

132. Flow separation is caused by:

Reduction of pressure in the direction of flow

Reduction of the boundary layer thickness

Presence of adverse pressure gradient

Presence of favourable pressure gradient

133. In case of flow over a flat plate, the Reynold number at which flow becomes turbulent is:

2300

3.2x105

7.5x105

2000

134. The critical angle of attack of an aerofoil is that where:

The lift becomes zero

The drag becomes zero

The drag begins to rise

The lift begins to drop

135. A normal shock can occur only when:

Flow changes from supersonic to subsonic

Flow changes from sonic to subsonic

Flow changes from subsonic to sonic

The flow is Trans-sonic

136. Flow over an elliptical body may be idealized by superimposing a free stream and:

A source

A doublet

A source and sink

A free vortex

137. Impingement of a jet on a flat plate may be expressed by:

pie xy

x2 y2

x3 y3

x y

138. Euler number is given as the ratio of:

Inertia force Gravity force

Pressure force inertia force

Inertia force Surface tension

Gravity force Inertia force

139. With the increase in the length of fin, fin efficiency:

Decreases

Increases

Remains unaffected

First increases and then decreases

140. Consider a cylinder of radius R with uniformly distributed heat source of heat generation rate and constant thermal conductivity K. Assume temperature as a function of radius only. The boundary conditions are; T Tw at r R and heat generated equals heat lost at surface. w The temperature distribution in the cylinder is given by:

<img src='./qimages/3399-140.jpg'>

141. In transient heat conduction, lumped capacity analysis is applicable with good accuracy when Biot number

is equal to 1

is less than 0.1

is greater than 0.1

is less than 1

142. General conduction equation in its simple form, delta2 T=0 (where T is temperature), is called:

Poisson's equation

Fourier's equation

Laplace equation

Kirchoff's equation

143. Air at 300 °C and 7 bar is expanded isentropically until the velocity is 300 m/s. Calculate the static temperature of the air at high velocity condition if Cp of air is 1.00

255 °C

295 °C

300 °C

None of the above

144. Prandtl number is connecting link between:

Velocity field and temperature field

Gravity field and temperature field

Gravity field and velocity field

None of the above

145. The significance of Reynold analogy is that it:

Tells whether flow is laminar or turbulent

Relates heat transfer to momentum transfer

Relates heat transfer and mass transfer

Relates heat transfer and frictional loss

146. For mixed (free and forced) convection in horizontal tubes of diameter d and length Graetz number is defined as:

Re. Pr.d/L

Gr. Pr. Re. d/L

Gr. Re.d/L

Gr. Pr.d/L

147. Radiations are incident from a small area dA1 to a disc A2 of diameter D kept at a distance R. The shape factor FdA1 will be:

D2/R2+D2





(d)D2/R2+4D2

148. Three radiation shields are placed between two infinite parallel plates. The emissivities of plates and shields are same. As compared to heat transfer without shields, the heat transfer with shield will become: . .

1/3

1/9

1/4

None of the above

149. For a double pipe, counter flow heat exchanger with C 1 Cmin C max) the effectiveness is equal to:NTU

NTU/NTU

1+1 NTU

NTU/ NTU

NTU +1/NTU

150. Dittus Boelter equation for heating of a fluid in a tube is given as follows:

Nu=0.023 Re0.8 Pr0.4

Nu=0.023 Re0.8 Pr0.3

Nu=C Ren (where C is a constant and n is a real number)

Nu=C loge Ren

151. Triple point and critical point pressure of carbon dioxide are:

4.58mm Hg and 221.2 bar respectively

5.18 bar and 221.2 bar respectively

1 bar and 50 bar respectively

5.18 bar and 73.8 bar respectively

152. In winter air conditioning, the inside design conditions are given by the following:

25°C DBT, 50% RH

25°C DBT, 60% RH

21°C DBT, 50% RH

21°C DBT, 60% RH

153. Effective temperature in respect of air conditioning is the temperature of:

Unsaturated air

Saturated air

Dry air

Either or above

154. Normal boiling point of different refrigerants are given below. Which pairs are correct?

NH3 40.8°C
R-12 29.8°C
R-22 33.3°C
R-134a 26.2°C

and are correct

and are correct

and are correct

and are correct

155. Actual expansion process in a throttling device is:

Reversible adiabatic expansion

Isenthalpic expansion

Fanno line expansion

Isothermal expansion

156. What will be the depth of a point below water surface in sea, where pressure intensity is 1.006 MN/m2? (Specific gravity of sea water 1.025)

10 m

100 m

1000 m

1 m

157. Which of the following expression correctly defines the relationship between internal pressure intensity and the radius of spherical droplet 1

p 1/r

p infinity r

p infinity 1/r2

p infinity r2

158. In case of multi-stage vapour compression system, flash intercooling is beneficial in case of those refrigerants only for which:

Latent heat of vapourization is more

Latent heat of vapourization is less

Thermal conductivity is high

Thermal conductivity is low

159. For an incompressible flow, which of the following is correct?

<img src='./qimages/3399-159.jpg'>

160. The velocity components in a two dimensional flow field for an incompressible fluid are expressed as

u 2x -x2y

u xy2 2y

These functions represent:

Rotational flow

Irrotational flow

Either rotational or irrotational flow

Neither rotational nor irrotational flow

161. Constant volume cycle is also known as:

Otto cycle

Joule cycle

Rankin cycle

Atkinson cycle

162. An engine working on stirling cycle between the same temperature limits as that of Carnot cycle, has air standard efficiency:

More than Carnot cycle

Equal to Carnot cycle

Less than Carnot cycle

Depends upon other factor also

163. The frictional resistance in case of turbulent flow is independent of

Pressure of flow

Density of fluid

Temperature of fluid

Area of surface in contact

164. The velocity at which the flow changes from laminar to turbulent for a given fluid at a given temperature is known as:

Maximum velocity

Minimum velocity

Average velocity

Critical velocity

165. The head loss due to turbulent flow as compared to laminar flow is:

More

Less

Equal

Unpredictable

166. In a laminar flow, the velocity at any point is:

Constant in magnitude but varying in direction

Constant in magnitude as well as in direction

Constant in direction but varying in magnitude

Variable in magnitude as well as in direction

167. The similarity of shape between the model and prototype is known as:

Dynamic similarity

Kinematic similarity

Geometric similarity

None of the above

168. The thickness of boundary layer is proportional to:

Its distance from the leading edge

Square of its distance from the leading edge

Four times its distance from the leading edge

Square root of its distance from the leading edge

169. The flow within the boundary layer is:

Only turbulent

Only laminar

Either or

None of the above

170. The total drag on a plate held normal to the flow is equal to:

Pressure drag

Viscous drag

Pressure drag x viscous drag

Viscous drag /Pressure drag

171. The coefficient of drag and lift are functions of:

Frouds number

Reynolds number

Weber number

Euler number

172. The aspect ratio of a wing is expressed as:

l/A

l/A2

l2/A

l2/A2

173. Beyond the stall point, the drag coefficient:

Decreases rapidly

Increases rapidly

Remains same

None of the above

174. The process in which heat energy is transmitted by means of electromagnetic waves is known as:

Heat conduction

Heat convection

Heat radiation

None of the above

175. Heat conduction in gases is due to:

The elastic impacts of molecules

The motion of electrons

The mixing motion of different parts of a fluid

The electromagnetic waves

176. In which case the medium is not required for the transfer of heat energy:

Conduction

Convection

Radiation

None of the above

177. According to Fourier's law, the quantity of heat flow through a surface area and thickness is given by the relation:

Q KA

Q A/k

Q A

Q KA

178. According to Newton's law of cooling, the rate of heat transfer from a solid surface of area at a temperature t1, to a fluid at temperature t2 is given by:

Q hA

Q hA

Q h A

Q A h

179. The opaque body is that which:

Absorbs all radiations

Reflects all radiations

Transmits all radiations

Partly reflects and partly absorbs the radiation

180. According to Stefan Boltzman law the relation between the total emission from a black body per unit area and per unit time and the absolute temperature is given as:

<img src='./qimages/3399-180.jpg'>