CMRL Mechanical-Engineering Contributed by Sharanya updated on Mar 2019

CMRL-Chennai Metro Rail Limited .  free sample questions with answers. CMRL model questions for practice,CMRL not the orginal or previous years questions,CMRL model questions for learn and practice.

1.   The ratio of specific heats Cp/Cv
a)    varies linearly with temperature  
b)    varies linearly with pressure
c)    first increases and then decreases with increase in temperature
d)    first increases and then decreases with increase in pressure
e)    remaining constant         (Ans)

2.    According to St. Venant's Principle
a)    deformations of all materials for a given loading are equal
b)    it is a method for determining the stress conditions at the end of the plates
c)    stress conditions approach uniformly as the distance from the point of application of the force increase        (Ans)
d)    after a point of time the stresses in a  loaded member tend to relieve themselves
e)    stress conditions vary widely in unpredictable way as the distance from the point of application of force increases.

3.    The maximum height of a syphon for a fluid of specific gravity ρ  under atmospheric condition is
a)    ρ/10 metres
b)    10 (1+ρ) metres
c)    10/(1-ρ) metres
d)    10/ρ metres        (Ans)
e)     10/(1+ρ) metres

4.    An impulse is defined as
a)    force  X  displacement
b)    force   X velocity
c)    mass X velocity
d)    force X time        (Ans)
e)    torque X time

5. Which rays have the least wavelength
a)    infra -red
b)    ultraviolet
c)    X-rays
d)    cosmic rays      (Ans)
e)    radio waves

6.   Steel reinforcing bars are used in reinforced cement concrete because  
a)    the concrete is weak in compression
b)    it increases the density of the concrete
c)    it increases life of concrete
d)    it facilitates in quick setting of R.C.C
e)    the concrete is weak in tension       (Ans)

7.    The process in which the molecules of a compound become large is known as
a)    Coalescence
b)    Polymerisation       (Ans)
c)    charging
d)    atomisation
e)    expansion

8.    In a 8 x37 wire rope, the number 8 indicates the
a)    diameter of the wire rope in mm
b)    number of strands       (Ans)
c)    number of wires
d)    guage number of the wire
e)    diameter of strand

9.    The compressibility of a substance is proportional to
a)    the poisson's ratio
b)    the modulus of elasticity
c)    the reciprocal of the modulus of elasticity
d)    the bulk modulus of elasticity
e)    the reciprocal of the bulk modulus of elasticity         (Ans)

10.  A body which absorbs all readiation falling on it is known as
a)    opaque body
b)    black body      (Ans)
c)    transparent body
d)    ideal body
e)    polished body

11.  A cylindrical section having no joint is known as
a)    Perfect section  
b)    jointless section
c)    ERW section
d)    seamless section       (Ans)
e)    continuous section

12.   If two objects are weighed in water and both of them lose the same weight, then the two objects must have identical
a)     specific gravities 
b)    weights in air
c)     volumes        (Ans)
d)     densities
e)     weights in water

13.  The purpose of providing sleeves around anchor bolts that bolt steel columns to footings is to 
a)    allow for minor lateral adjustments of anchor bolts           (Ans)
b)    provide better bearing of base plate on the footing
c)    provide greater bond between anchor bolt and footing
d)    allow the proper setting of the column
e)    provide reinforcement

14.   In order to provide arrangement for pulling etc. the ends of two rods are threaded with right handed thread and left handed thread. Both the rods are coupled together by
a)    turnbuckle         (Ans)
b)    thimble
c)    wing nut
d)    eyebolt
e)    knuckle joint

15.  A 1000 kg block resting on a horizontal plane has a static coefficient of friction of 0.33 and is acted on by a horizontal force of 200 kg. Under the above conditions, the frictional resistance is
a)    200 kg         (Ans)
b)    more than 200 kg 
c)    500 kg
d)    less than 200 kg
e)    1000 kg

16.  The basic purpose of using a flywheel on rotating machinery is to
a)    allow rapid acceleration
b)    store and release energy as required          (Ans)
c)    match output and input
d)    balance the rotating parts
e)    control the rotational speed  

17.   Steel columns are tied to concrete foundations by
a)    grout
b)    anchor bolts         (Ans)
c)    cement paste
d)    bolts
e)    eyebolt

18.    In a loaded horizontal, homogeneous rectangular beam, the horizontal shearing stress at any cross-section perpendicular to the neutral axis has a maximum value at the neutral axis and in comparison to average shearing stress at that section it is
a)    1.5 times         (Ans)
b)    double
c)    2.5 times
d)    thrice
e)    four times

19.   Two bodies of identical shape but different densities are dropped from a tower. Which of the following is true ?
a)     as per Stoke's law they will achieve the same terminal velocity and reach the ground at the same time            (Ans)
b)    the less dense one will arrive first
c)    the more dense one will arrive first
d)    they will become attracted to each other and arrive at the same time.
e)    Which one arrives first would depend on atmospheric conditions.

20.  If speed of a centrifugal pump is doubled, then
a)    Power required to operate it is doubled
b)    the volumetric discharge is increased 4 times
c)    the head becomes 4 times as great          (Ans)
d)    specific speed becomes 4 times
e)    all of the above

21.   In a laminated spring, the various strips are made of different length for the following reason
a)    reduction in weight  
b)    ease in fabrication
c)    material economy
d)    space consideration
e)    equal distribution of stress          (Ans)

22.   Which of the following metals has the greatest specific gravity
a)     Zinc 
b)    lead 
c)    iron
d)    mercury         (Ans)
e)    nickel

23.  Material with maximum density is
a)    lead
b)    osmium         (Ans)
c)    uranium
d)    tungsten
e)    titanium

24.  Toughness of a material can be measured with the help of
a)    Vickers pyramid hardness test
b)    universal testing machine          (Ans)
c)    nothced -bar tests
d)    standard spiral tests
e)    scratch test 

25.    Notched -bar tests are frequently used for testing
a)    the impact strength of a material         (Ans)
b)    the hardness of a material
c)    the machinability of a metal
d)    the corrosion resistance of the material
e)    the endurance limit of the material

26.  Lack of toughness in material is usually referred to as
a)    ductility
b)    brittleness         (Ans)
c)    malleability
d)    plasticity
e)    hardness

27.  The diameter of a shaft in any power transmission system is proportional to
a)    speed of the shaft  
b)    torque to be transmitted
c)    horse power to be transmitted          (Ans)
d)    allowable shear stress of the shaft material
e)    polar moment of inertia

28.   In riveted structural steel work, the type of member that usually connects a beam to column is
a)    an angle         (Ans)
b)    a channel
c)    a gusset plate 
d)    a tee
e)    a knuckle

29.   Unwin's Rule for riveted joints gives the relationship between
a)    diameter of the rivet and the load
b)    thickness of the plate and the load
c)    thickness of plate and number of rivets
d)    diameter of rivet and thickness of plate          (Ans)
e)    number of rivets and size of rivet

30.  The Rock well number refers to a material's
a)    malleability
b)    toughness
c)    piezo-electric constant
d)    plasticity
e)    hardness          (Ans)

31.  The property of steel that makes it suitable for use in cable is its strength in
a)    Compression
b)    tension         (Ans)
c)    shear
d)    torsion
e)    bending

32.   The maximum efficiency of a screw jack depends upon
a)    helix angle
b)    angle of friction         (Ans)
c)    pitch of threads
d)    velocity of ratio
e)    mechanical advantage

33.  A ball is moving in a straight path down an inclined plane with constantly increase speed. Pick up the incorrect statement.
a)    its acceleration is increasing          (Ans)
b)    its acceleration is constant
c)    its kinetic energy is increasing
d)    its potential energy is decreasing
e)    sum of potential and kinetic energies is constant

34.  The frequency (f) of a vibrating string is related to the mass/unit length of the string (m). Which of the following relationship is correct ?
a)    f is proportional to m  
b)    f is proportional to 1/m
c)    f is proportional to √m
d)    f is proportional 1/√m         (Ans)
e)    f is proportional 1/m3/2

35.  It dT the drop in temperature and dp the drop in pressure in a throttling process, then Joule-Thomson coefficient is defined as
a)    dp/dT
b)    dT/dp        (Ans)
c)    1 + dp/dT
d)    1 + dT/dp
e)    1 - dT/dp

36.   The isentropic expansion of superheated steam is fairly represented by pvn =  constant, when n=
a)    1.315       (Ans)
b)    1
c)    1.27
d)    1.41
e)    1.35

37.  In Figure line AB represents the following process  

a)    heating above the dew point       (Ans)
b)    cooling above the dew point
c)    cooling below dew point (dehumidification)
d)    cooling and dehumidifying
e)    humidification (adiabatic saturation)

38.  In Diesel engines, injection of fuel continues till
a)    the spark plug gives out a spark  
b)    the compression is complete
c)    the clearance volume is filled with the fuel oil
d)    the cut off point is reached          (Ans)
e)    discharge valve opens

39.  The heat is supplied partly under constant pressure and partly under constant volume in the following cycle
a)    Carnot cycle
b)    Diesel cycle
c)    Dual cycle         (Ans)
d)    Otto cycle
e)    Rankine cycle

40.  A critical depth meter is associated with
a)    water hammer
b)    tranquil flow
c)    surge
d)    hydraulic jump         (Ans)
e)    steep gradient

41.  In multi-cylinder engines a particular sequence in the firing order is necessary
a)    to give good distribution of fuel to all the cylinders
b)    to give better balance of the engine
c)    to provide the best engine performance         (Ans)
d)    to operate the ignition system smoothly
e)    to obtain uniform torque diagram

42.  As the number of cylinders in multi-cylinder engines increases, the power -to - weight ratio
a)    remain the same
b)    decrease
c)    increase         (Ans)
d)    becomes zero
e)    first decreases and then increases

43.  Piston is connected to the connecting rod by
a)    sleeve bearing
b)    cap bolts
c)    small end bearings
d)    big end bearings
e)    gudgeon pins         (Ans)

44.  Engine misfiring is likely to result from
a)    spark plug gap too narrow
b)    spark plug gap too wide          (Ans)
c)    incorrect mixture
d)    vapour lock in fuel line
e)    spark plug running too hot or too cold.

45.  Rotameter is used for measuring
a)    density
b)    viscosity
c)    flow         (Ans)
d)    velocity
e)    pressure

46.  Bar is the Unit of
a)    Pressure          (Ans)
b)    power
c)    energy 
d)    viscosity
e)    level

47.  With continuous usage of the spark plug, the spark plug gap size
a)    decrease
b)    increase         (Ans)
c)    remains the same
d)    becomes zero
e)    increases/decreases depending on engine rating

48.   The control rods in nuclear power plants are made of
a)    lead
b)    magnesium
c)    graphite
d)    boron or cadmium       (Ans)
e)    deuterion 

49.   In thermodynamics, Carnot cycle is also called as
a)    Constant pressure
b)    Constant volume cycle
c)    Constant temperature cycle 
d)    constant heat cycle       (Ans)
e)    constant entropy cycle

50.   Otto cycle used in petrol engines is also known as
a)    constant pressure cycle
b)    constant volume cycle        (Ans)
c)    dual cycle
d)    diesel cycle
e)    constant heat cycle

51.  The air standard efficiency of an I.C. Engine working on the Otto cycle is a function of
a)    working substance
b)    volume of cylinder
c)    compression ratio       (Ans)
d)    the quality of fuel used in the engine
e)    ratio of maximum and minimum temperature

52.  Pick out the wrong relationship
a)    E = 2G(1+P)
b)    G = E/2 (1- μ)      (Ans)
c)    μ = (E - 2G) 2G
d)    K = E/3 (1-2μ)
e)    μ = (3K -E)/6K.
E = modulus of elasticity in tension or compression, G = modulus of elasticity in shear, K = bulk modulus of elasticity. (d) K = E/3 (1-2μ)  = poisson's ratio.

53.  Materials having elongation less than 5% are called brittle. In such cases, factor of safety is based on
a)    yield stress
b)    endurance limit
c)    limit of proportianality
d)    ultimate stress      (Ans)
e)    proof stress

54.  The stiffness of beam varies as
a)    1          ,     1             and (depth, h)3      (Ans)
     load (P),   (span,l) 3  

b)    1   ,  1  ,  h2
          P     l

c)    P, l3, h3 

d)    1   ,  1  ,   1
          P     l 2    h3

e)    1   ,  1  ,   h3
          P     l 3   

55.    If the span of a beam is constant, a shallow beam compared to a deeper beam will be subjected to
a)    less deformation
b)    greater deformation      (Ans)
c)    more or less same deformation
d)    equal deformation
e)    unpredictable

56.  If depth of a beam is constant, then a beam of double span will attain a given deflection with
a)    on-quarter the stress      (Ans)
b)    half the stress
c)    one-eighth the stress
d)    one-third the stress
e)    one-sixth the stress

57.   In the beams, the order factors remaining same, the deflection varies as
a)       1           and                 1                      
         Stress (s)            modulus of elasticity (E)
b)    s,   1        (Ans)
c)     s2,   1 
d)    s,   1 

e)    s, E

58.  The most usual cause of excessive tyre wear is
a)    less air pressure inside the tyre          (Ans)
b)    excessive air pressure inside the tyre
c)    excessive speed of vehicle
d)    improper braking system used
e)    rough roads

59.   the brake efficiency is 100 per cent when
a)    the brakes are in excellent condition
b)    the driver brings the vehicle to a dead stop in 1 second
c)    the stopping distance is 10 metres at a speed of 10 km/hr
d)    the rate of deceleartion is 1 m/sec 2
e)    the rate of deceleration is 10 m/sec 2       (Ans)

60.  Sodium in fuel oil for gas turbines is harmful. It is removed before firing fuel by
a)    using additives
b)    washing oil with water and removing water by centrifuging        (Ans)
c)    heating oil and cooling it suddenly
d)    electrostatic precipitation
e)    allowing oil to settle for long time

61.  In the expression P1V1n = P2V2n for an isentropic expansion, 'n' is :
a)    (Cp - Cv) /Cp
b)    (Cv-Cp)/Cv
c)    Cv-Cp
d)    Cp/Cv       (Ans)
e)    1- Cp/Cv

62.   In which process the solid changes directly to the gaseous form
a)    sublimation       (Ans)
b)    polytropic change
c)    allotropic change
d)    recrystallization
e)    evaporation

63.   Air fuel ratio in petrol engine is controlled by
a)    fuel pump
b)    injector
c)    governor
d)    carburettor       (Ans)
e)    controller

64.   The ratio of Cp/Cv for air and most common gases below 500oC is of the order of
a)    0.87
b)    1.04
c)    1.00
d)    1.27
e)    1.40       (Ans)

65.   A hot body will radiate heat most rapidly if its surface is
a)    rough and white
b)    white and polished 
c)    grey
d)    black and rough       (Ans)
e)    black and polished

66.  The most efficiency thermodynamic cycle is
a)    Carnot      (Ans)
b)    Stirling
c)    Diesel
d)    Otto
e)    Rankine

67.  In rainy season, desert coolers become ineffective because of
a)    fine weather
b)    low temperature
c)    low humidity
d)    high humidity      (Ans)
e)    none of the above

68.  Greater flexibility in plant layout is achieved in the case of
a)    layout by fixed position
b)    process layout      (Ans)
c)    product layout
d)    group layout
e)    functional layout

69.  The concept of 'ABC' analysis is applied mostly in
a)    plant layout and materials handling
b)    ergonomics
c)    methods time measurement
d)    inventory control      (Ans)
e)    process planning

70.  The scientific study of the relationship between man and his working environment is known as :
a)    industrial psychology
b)    ergonomics      (Ans)
c)    industrial engineering
d)    work study
e)    industrial management

71.   In theory of metal cutting the shear plane angle is the angle between
a)    shear plane and job surface       (Ans)
b)    shear plane and vertical plane
c)    shear plane and horizontal plane
d)    shear plane and tool surface
e)    shear plane and tool axis

72.   The tool signature comprises
a)    5 elements
b)    6 elements
c)    7 elements      (Ans)
d)    8 elements
e)    9 elements

73.  In tool signature, the nose radius is indicated
a)    in the first position
b)    in the last position      (Ans)
c)    in the middle
d)    second from end
e)    second position

74.  Which one of the following is not a part of micrometer
a)    thimble
b)    spindle
c)    sleeve
d)    beam      (Ans)
e)    anvil

75.   Point angle of drills is usually more while drilling
a)    mild steel
b)    aluminium    
c)    soft cast iron
d)    marble
e)    hard alloys      (Ans)

76.  Mohs scale of hardness in an arbitrary one which is used to describe the hardness of several mineral substance on a scale of
a)    1 through 5
b)    1 through 10     (Ans)
c)    1 through 25
d)    1 through 50
e)    1 through 100

77.  The specific gravity of liquids is usually measured by means of a
a)    hygrometer 
b)    thermometer
c)    hydrometer     (Ans)
d)    piezometer
e)    Baume meter

78.    One of the arbitrary scale used for scale reading of a hydrometer is API (Americal Petroleum Institute). Corresponding to 10 A.P.I. degree, specific gravity is 1,000. As the API degree increase beyond 10 the specific gravity value.
a)    increases
b)    decreases     (Ans)
c)    remains same
d)    first increases and then decreases
e)    first decreases and then increases

79.   A structure is said to be statically indeterminate when
a)    it is not properly loaded
b)    it is imbalanced
c)    forces are so huge that it may collapse
d)    it is not properly supported
e)    the conditions are not sufficient for the determination of the supports or other forces      (Ans)

80.   If Ix and Iy be the moments of inertias about any two axes it right angles to each other in the plane of he area and intersecting at the pole, then polar moment of inertia Ip is equal to
a)     Ix + Iy      (Ans)
b)    Ix + Iy
c)     Ix   X   Iy
d)    Ix   X   Iy
e)    ∫Ix Iy

81.   In every plane area, a given point being taken as the origin, there is at one pair of rectangular axes in the plane of the area about one of which the moment of inertia is a maximum , and a minimum about the other. There moments of inertia are called the
a)    principal moments of inertia     (Ans)
b)    moments of inertia about parallel axes
c)    polar moment of inertia
d)    product of inertia
e)    none of the above

82.  The moment of inertia about axis YY of a rod of mass M, length L, with shape and size of the cross section un known (assuming approximately that the wieght is all concentrated along the axis of the rod), placed horizontally is equal to
a)    Ml2
b)    Ml2
c)     Ml2     (Ans)
d)     Ml
e)     Ml2
83.   If r1 and r2 be outer and inner raii of a thick hollow sphere and ρ its density, then its  M.I. about a diameter is equal to
a)    ρπ  (r15 - r25) 
b)    ρπ   (r15 - r25) 
c)    2  ρπ (r15 - r25) 
d)     2  ρπ (r15 - r25) 
e)    8  ρπ (r15 - r25)       (Ans)

84.   The centre of percussion of the homogeneous rod of length l and mass m, suspended vertically from top, will be at following distance from the top
a)      l/2 
b)      l/3
c)      2l/3     (Ans)
d)      3l/4
e)      5l/8

85.   The centre of percussion of a solid cylinder of radius 'r' resting on a horizontal plane, (Refer Fig.) will be at following height above the plane.

a)     r
b)    2 r
c)    3r     (Ans)
d)    4 r
e)    8 r

86.   Centre of percussion and axis of oscillation
a)    coincide
b)    are interchangeable     (Ans)
c)    act at the centre of gravity of body
d)    are radius of gyration apart
e)    are non interchangeable

87.   If k = radius of gyration of a body, q = distance from the axis of oscillation of the centre of percussion, and x = distance from the same axis to the centre of gravity, then following relation holds good
a)    k = √qx     (Ans)
b)    k =  qx 
c)    k = q + x
d)    k = √qx
e)    k = √q

88.   If I1, I2 and I3 represent the principal  moments of inertia of a gyroscope spinning with a constant angular velocity 1 about axis I, and if the gyroscope is about the third axis, then a

vector moment results along the second axis such that M2 =
a)    l2 (2) + (I1 - I3) ω3ω1     (Ans)
b)    l2 (2) + (I1 - I3) ω2
c)    l2 (2) + (I1 - I3) ω3
d)    l1 (1) + (I2 - I3) ω2ω2
e)    l3 (1) + (I2- I3) ω2ω3
(subscripts 1, 2 and 3 represent a right hand set of reference axes)

89.   For a symmetrical body having M.I. = I in all three mutually perpendicular planes, if axes of spin and percussion are at right angles having rate of spin = ω and rate of spin =Ω, the gyroscopic moment is equal to
a)    IωΩ     (Ans)
b)    Iω/Ω
c)    Iω/ω
d)    I(ωΩ)2
e)    I/ωΩ

90.  The coefficient of friction at higher velocities with increase in velocity    
a)    increase  
b)    decrease     (Ans)
c)    remains unaffected
d)    increases first and then decrease
e)    may increase/ decrease depending on pressure acting on the surfaces

91.  The hydraulic radius of a pipe of diameter 'D' flowing full is
a)    D
b)    D/2
c)    D/3
d)    D/4     (Ans)
e)    D/8

92.  The velocity profiles for laminar flow and turbulent flow respectively are
a)    parabolic, logarithmic      (Ans)
b)    logarithmic, parabolic
c)    linear, parabolic
d)    logarithmic linear
e)    elliptical, logarithmic

93.   The hydraulic radius of a circular pipe is equal to
a)    its diameter (D)
b)    D/2
c)    D/4     (Ans)
d)    D/3
e)    2D/3

94.   In the case of orifice plates, the maximum differential is obtained by using following types of tap offs
a)    1D, 1/2D taps
b)    1/2 D, D taps
c)     flange taps
d)     Vena contracta taps      (Ans)
e)     ID, ID taps

95.   In a siphon, the air pump or ejector is opened occasionally to remove accumulated air and vapour for priming the pipe. This is done
a)    to increase flow
b)    to increase head of siphon
c)    to increase efficiency of the system
d)    to reduce noise
e)    because the flow will not take place unless the siphon is full of water      (Ans)

96.  The divergent cone in venturi tube is provided to reduce the overall pressure loss of the meter. The coefficient of discharge, due to removal of the divergent cone will
a)    increase
b)    decrease
c)    unpredictable
d)    remain unaffected      (Ans)
e)    may increase/decrease depending on other considerations

97.   Whether the flow in an open-channel is critical, subcritical, or super critical is determined by
a)    Weber number
b)    Reynold number
c)    Mach number
d)    Froude number     (Ans)
e)    Hydraulic gradient

98.  In the case of open channel flow, the specific energy is defined as the energy of the fluid
a)    referred to the bottom of the channel as the datum      (Ans)
b)    divided by density
c)    divided by static head     (Ans)
d)    added with static head
e)    divided by the flow rate.

99.   For monoatomic gases, the specific heats with rise in temperature
a)    increase
b)    decrease
c)    remain unchanged   (Ans)
d)    first increase and then decrease
e)    first decrease and then increase

100. If Q1 is the heat input at temperature T1 to a Carnot engine and Q2 is the heat rejected at temperature T2, then which of the following is the correct statement.
a)     Q1  -  Q2  = constant
        T1      T2
b)    Q1  -  Q2
        T1      T2 
c)     Q1 +  Q2   = 0     (Ans)
        T1      T2
d)    Q1  -  Q2  
        T1      T2  
e)    Q1  X T1 = Q2 X T2

101.  If T0 is the lowest available temperature for heat discard and ?s   the net change in entropy, then the increase in unavailable energy in thermodynamic process will be equal to
a)    T/?s
b)    T0 X  ?s      (Ans)
c)    ?s /T0
d)    1 - T0 X ?s
e)    1+ T0 X ?s
         T0 X ?s
102.  Free energy or the Helmholtz function in thermodynamic processes is defined as
a)     u-TS
b)     u + TS
c)     u + pv
d)     h - TS     (Ans)
e)     TS - u
       (Where   u =  internal energy
                     T =  temperature
           and    S = entropy)
103.    Availability of a system or quantity of energy in a thermodynamic process is defined by
a)       Gibbs function       (Ans)
b)       Helmholtz function
c)       Maxwell equation
d)      Clapeyron equation
e)      Carnot cycle

104.   According to first law of thermodynamics
a)      wherever energy is transformed from one form to another, energy is always conserved
b)      energy can neither be created not destroyed
c)      the sum total of all energy remains constant
d)     any one  of the above      (Ans)
e)     none of the above

105.  The free enthalpy or Gibbs function is defined as
a)     h-TS     (Ans)
b)     u - TS
c)     pv + TS
d)     h + TS
e)     u + TS
(Where h = enthalpy, u = internal energy, T=temperature, s=entropy, p=pressure, v=volume)

106.  Which of the following cycle is used as the basis for analysis of gas turbine opeation.
a)     Carnot
b)     Otto
c)     Diesel
d)     Joule     (Ans)
e)     Stirling

107. The discharge of saturated steam through an orifice, in terms of the area of orifice and steam inlet pressure is expressed by
a)    Napier's equation
b)    Grashoff's formula
c)    Rateau's formula
d)    any one of the above      (Ans)
e)    none of the above

108.  When steam expands rapidly in turbine nozzles,  it becomes supersaturated (i.e. the condensation required by the ordinary theory of adiabatic expansion does not occur on account of the rapidity of expansion). The effect of supersaturation  in turbines is
a)    increase in efficiency
b)    increase in dryness fraction
c)    loss of energy     (Ans)
d)    increase of energy
e)    heating of steam

109. For every gas, there is one temperature at which no temperature change occurs during a Joule-Thomson expansion. Below this temperature, a gas cools on throttling and above this, its temperature rises. The temperature at which no temperature change occurs is known as
a)    saturation temperature
b)    throttling temperature
c)    supersaturation temperature
d)    isotatic temperature
e)    inversion temperature     (Ans)