1. The following is not true in case of thermodynamic work:

!PdV for a reversible process only

W if dV

W for a free-expansion process

W is an inexact differential

2. The internal energy of an ideal gas is a function of:

Pressure only .

Volume only

Absolute temperature only

Pressure, volume and temperature only

4. The correct statement regarding entropy is that:

Entropy is a paTh function

Entropy can be obtained from a direct measurement of Q andT

During a change of a state of a system, the entropy change is the same whether that change has occurred via a reversible process or an irreversible one

Entropy of an isolated system is zero

5. One Garnot heat engine operates between 1600 K and while the 'other operates between T2 and. 400 Both have the same heat input and heat rejection then T2 is:

800 K

1000 K

12'00 K

1400 K

6. Gasohol is a mixture of:

90% ethanol 10% gasoline

10% ethanol 90% gasoline

40% ethanol 60% gasoline

50% ethanol 50% gasoline

7. Disadvantage of hydrogen as a fuel in IC engine:

Storage is.easy

Low NO emission

Detonating tendency

Easy handling

8. Major constituent of natural gas is

Ethane

Methane

Propane

Butane·

9. Major disadvantage of LPG as a fuel in automobile is

Reduction in life of the engine

Less power compared to gasoline

Both and

Knocking tendency

10. The method of governing for a petrol engine is:

Hit and misgoverning

Quality governing

Quantity governing

Misgoverning

11. Fuel is injected in a four-stroke CI engine:

At the end of suction stroke

At the end of compression stroke

At the end of expansion stroke

At the end of exhaust stroke

12. Main advantage of pintaux nozzle

Better· cold starting performance

Ability to distribute the fuel

Good penetration

Good atomization

13. With increase in compression ratio flame speed:

Increases

Remains same

Decrease

First increases and then remain constant

14. Scavenging means:

Using fresh air for compressor

To reduce detonation

Using air for throwing burnt gases out of cylinder during exhaust stroke

Using correct air fuel mixture

15. At flash point temperature:

Fuel ignites without any spark

Fuel emits vapours which produce an inflammable mixture with air

Fuel vaporize sat very high rate

The fuel spontaneously ignites for longer time

16. Cetane number is the measure of

Delay period

Detoriation

Flash point

Ignition quality

17. If diesel is fed into petrol engine then the engine will

Not run

Knock

Detonate

Give lot of smoke

18. Duration between the time of injection and time of ignition in a diesel engine is called:

Lead period

Delay period

Combustion period

Period of compression

19. If compression ratio is kept same then thermal efficiency of

Otto cycle is less than Dual cycle

Otto cycle is same as that for Diesel cycle

Otto cycle is less than that of Diesel cycle

Otto cycle is more than that 01 Diesel cycle

20. Stoichiometric ratio means:

Chemically correct air-fuel ratio i by mass

Air-fuel ratio for maximum

efficiency Chemically correct air-fuel ratio

by volume Oxygen-fuel ratio by volume

21. The MLTS system the dimension of thermal conductivity is

ML-1T-1S-3

MLT-1S-1

MLS-1T-3

MLS'-1T

22. Two plane slabs of equal area but with thermal conductivities in the ratio 1 2 are held together with temperature between the two outer surfaces being T1 and Tz. If the junction temperature between the two T1 T2/2 surfaces is desired to be" .. 2 then their thick nesses should be in the ratio of

2

1

1 1

3:1 .

23. Thermal diffusivity of a substance is

Inversely proportional to the thermal conductivity

Directly proportional to the density of the substance

Inversely proportional to the specific heat

Directly proportional to kinematic viscosity

24. If the temperature of a solid surface increases from 270 C to 6270 its emissive power increases in the ratio:

1:3

1:9

27

81

25. It is desired to reduce the radiation energy exchange between two infinite parallel planes by inserting radiation shields of the same emissivity. The number of shields required for 80% reduction will be

2

3

4

5

26. Fins are provided on heat transferring surface to

Increase surface area to promote the rate of heat· transfer

Increase temperature gradient so as to enhance heat transfer

Increase turbulence in f10yv for enhancing heat transfer

Decrease the pressure drop of fluid

27. If the radius of any current carrying wire is less than the critical radius, then the addition of electrical· insulation will enable the wire to carry a higher current because the:

Thermal resistance of the . insulator is reduced

Thermal resistance of the insulator is increased

Heat loss from the wire is reduced

Heat loss from the wire is increased

28. An ideal absorber of radiation is also an ideal emitter. It is known as

Kirchhoff's law

Wien's law

Planck's law

Lambert's law

29. A thin flat plate is hanging freely in air at 27° C. Solar radiation falls in one of its sides at the rate of 500 W/m2. For maintaining the temperature of the plate constant at 32° the value of heat transfer coefficient is

25W/m2

50W/m2

100W/m2

200W/m2

30. The Nusselt number in natural convection is a function of:

Reynolds and Pandtle numbers

Grashof and Prandtl numbers

Reynolds and Grashof numbers

Grashof and Biot numbers


31. <img src='./qimages/3399-31.jpg'>

32. Refrigerant flow is controlled by

Capillary tube

Condenser

Solenoid

Expansion Valve

33. In a reversed Carnot refrigeration cycle, the condenser and evaporator are at 27°C and respectively. The COP of this cycle is:

6.5

7.5

10.5

15.5

34. Usual secondary refrigerant in milk chilling unit is

Ammonia solution

Sodium silicate

Glycol

Brine

35. .In cooling tower, "approach" is the temperature difference between the:

Hot inlet water and cold outlet water

Hot inlet water and wet bulb temeprature

Cold outlet water and wet bulb temperature

Dry bulb and wet bulb temperature

36. A hermetically sealed unit implies:

Compressor is sealed

Motor is sealed

Refrigerant cycle is sealed

Both compressor and motor are sealed

37. Chemical formula of Freon-12 is:

CCI2 F2

CCIF

CCIF

CCIF 33

38. Heating of air without changing its moisture content takes place on a psychometric chart along:

A horizontal line of constant dew point .

Rising line

Falling line

Curved line

39. Dry compression is preferred due to

High volumetric efficiency

High mechanical efficiency

Less chance of damage of the compressor

All of the above

40. Pipe material for the refrigerator with ammonia solution as working fluid should not be

Mild steel

Copper

Aluminum

Brass
41. Under cooling of refrigerant leads to

Decrease refrigerating effect

Reduce work done

Reduce COP

Increase the COP of the cycle

42. COP for refrigerator and heat pump are related as

COPh COP r

COPh COP r

COPh =COPr+1

COPh 1/COPr

43. if T1 and T2 are dry bulb temperature of air entering and leaving the coil and T3 is ADP temperature (temperature of cooling coil), then T1 bypass factor for sensible cooling of air is:


<img src='./qimages/3399-43.jpg'>

44. During mixing of steams in case of air conditioning, the process is associated with

Throttling

Adiabatic

Isobaric

Isochoric

45. The presence of moisture in refrigeration effect is felt at

Evaporator

pipes

Expansion valve

Compressor unit

46. The humidity ratio is also expressed as where Ps is the partial pressure . of superheated vapour and p is the barometric pressure of mixture:


<img src='./qimages/3399-46.jpg'>

47. If we have 100% RH, then OPT, WBT and OBT can be related to each other as:

OBT<OPT<WBT

OBT =OPT =WBT

OPT> WBT OBT

None of the above

48. The desuperheating coil in a condenser performs the function of:

Improving the heat of superheat of the refrigerant before it goes into condenser

Removing heat from condenser

Improving condenser performance

To humidity the refrigerant before it goes into condenser Contd.

49. In split system of air-conditioner, the condensing unit is located:

Inside the conditioned area to be

Outside the conditioned area to be

Near the refrigerator

None of the above


50. The refrigerant R-717 represents:

Carbon dioxide

Carbon monoxide

Ammonia

Methane


51. The maximum thickness of boundary layer in case of a pipe of radius R is:

R

1/3 R

0,1 R

2/3 R

52. How does pressure intensity varies when liquid rotates at an angular velocity of a vertical axis?

Directly with radial distance

Directly with square of the radial distance

Inversely with square of the radial distance

None of the above

53. Pitot tube is used for measurement of:

Viscosity

Pressure

Flow

Velocity

54. The hydraulic mean depth of a circular pipe of diameter d running full is equal to

d/2

d/4

0.29 d

d

55. In order to increase sensitivity of U­tube manometer, one leg is usually inclined by angle e. Sensitivity of· .inclined tube to sensitivity of U-tube is equal to:

sin theta

cos theta

tan theta

1/sin theta

56. Euler's equation in differential form is given as:

dp/p2+v2dv+g dz

P dp+v dv+ g3dz 0

dp dv +9dz p

dp v2dv +g2dz 0 P

57. For dimensional analysis the Buckingham's n-theorem finds the resulting equation in form of

dimensionless para­meters

n dimensionless parameters

Geometric and kinetic variables

Mass, length and time . ..

58. .Ratio of inertia force to surface tension is known as

Weber's number

Mach number

Froude number·

Euler number

59. 81 unit of viscosity is

1 poise

10 poise

Centipoise

None of the above

60. For a liquid coming out of a nozzle, maximum height attained is

<img src='./qimages/3399-60.jpg'>

61. The equation of continuity is applicable when the flow:

Velocity is uniform at all cross sections

Is steady

Is one dimensional

All of the above

62. Cavitation is caused by

Low surface tension

High pressure

Low pressure

Low velocity


63. The Centre of bouncy is

Centroid of displaced volume of fluid

A point slightly above meta center

Centre of gravity of the body

All of the above

64. All the terms of energy in Bernoulli's equation have dimension of:

Force

Work

Length

Energy

65. Head loss at entrance to pipe is

<img src='./qimages/3399-65.jpg'>

66. Separation flow occurs when pressure gradient:

Becomes less than zero

Becomes zero

Does not flow continuity equation

Changes slowly

67. Drag force on a body is result of:

Fluid dynamic force acting on the object

A component of resultant fluid dynamic force in the flow direction

Pressure variation over the· surface of object due to horizontal force

None of the above

68. Sonic velocity C for adiabatic is mentioned as

routeyRT

yRT

route YRT2

[yRTr]1/3

69. The magnitude of velocity at stagnation point is. an immersed body is

Zero

Large

Small

Half of the initial value

70. In a two-dimensional velocity field with velocities u and v along the x and y direction respectively, the convective acceleration along the x-direction given by a v au


<img src='./qimages/3399-70.jpg'>

71. Curtis turbine is

Reaction steam turbine

Pressure velocity compounded steam turbine

Pressure compounded impulse steam turbine

Velocity compounded impulse steam turbine

72. For maximum blade efficiency for single stage impulse steam turbine with nozzle angle a is


<img src='./qimages/3399-72.jpg'>

73. Steam flow in a steam generator is controlled by using:

Drum level sensor

Feed water flow sensor

Stem flow sensor

All of the above

74. In steam turbines the reheat factor:

Increases with the increase in number of stages

Decreases with the increase in number of stages

Remains same irrespective of

number of stages None of the above

75. Which of the following indicates the. correct order in the path of the flue gas?

Super heater, economizer, air pre heater

Air pre heater, economizer, super heater

Air pre heater, super heater, economizer,

No definite order

76. In a centrifugal pump casing, the flow .of water leaving the impeller, is I

Rectilinear flow

Radial flow

Free vortex flow

Forced vortex Contd.

77. If0 is the diameter of impeller at inlet, w is the width of the impeller at inlet and Vf is the velocity of flow at inlet then discharge through a centrifugal pump is equal to

pie DVf

DVfw

PIE DVfw

PIE DW

78. When a centrifugal pump is started, there will be no flow ofwater until the pressure rise in the impeller is large enough to overcome the:

Manometric head

Total head

.Static head

Friction head

79. The specific speed of turbine is indicated as NJQ


<img src='./qimages/3399-79.jpg'>

80. If ALPHA is the angle of blade tip at outlet, then maximum hydraulic efficiency of an impulse turbine is

<img src='./qimages/3399-80.jpg'>

81. In reaction turbine:

The vanes are partly filled

Total energy of fluid is converted to kinetic energy in the runner

It is exposed to atmosphere

It is not exposed to atmosphere

82. In reaction turbine, draft tube is used:

To transport water downstream without eddies

To convert the kinetic energy to flow energy by a gradual expansion of the flow cross­section

For safety to turbine

To increase the flow rate

83. Which of the following is not a rotary pump?

Gear

Vane

Axial

Screw

84. Air vessels used in a reciprocating pumps are initially filled with:

Water

Vacuum

Compressed air

None of the above

85. A plot between power generated in MW and time is known as

Load curve

Load faCtor

Demand curve

Load duration curVe

86. The ratio of maximum load to rated plant capacity is known as

Load factor

Utilization factor

Maximum load factor .

CaRacity factor

87. Capacity or a hydroelectric plant in service in excess of the peak load is known as:

Operating reserve

Spinning reserve

Peak reserve

Cold reserve

88. In a Pelton wheel, the bucket peripheral speed is 10 mIs, the water jet velocity is 25 m/s and volumetric flow rate of the jet is 1.0 m3/s. If the jet deflected angle is 1200 and the flow is ideal, the power developed is:

15.0kW

22.5kW

7.5kW

37.5kW

89. If NPSH (Net Positive Suction Head) for a pump is not obeyed, then:

The pump gets cavitated

Proper head is not developed

Pump has low efficiency

More power is consumed

90. A hydraulic turbine generates 500 kW at 1500 rpm under a head of 60 m. During testing conditions, a scale model of 1:5 works under the head of 15 m. the power generated by the model will be

2kW

1.6kW

3kW

2.5kW