Technical Questions asked in Punj Lloyd

  1. A triangular open channel has a vertex angle of 90° and carries flow at a critical depth of 0.30m.The discharge in the channel is(Civil Engg.)
    1. 0.08 m3 /s
    2. 0.11 m3 /s
    3. 0.15 m3 /s
    4. 0.2 m3 /s

    Answer:  Option B.
    Critical depth-
    For discharge at critical depth means discharge is maximum for a given specific energy and specific energy is the minimum and condition to fulfill this aspect. We have
  2. 1 TCU is equivalent to the colour produced by(Civil Engg.)
    1. 1 mg/L of choloroplatinate ion
    2. 1 mg/L of platinum ion
    3. 1 mg/L platinum is form of chloroplatinate ion
    4. 1 mg/L of organo-chloroplatinate ion

    Answer: Option  C.
    TCU is the colour unit and represented by colour produced by 1 mg of platinum-cobalt in the form of chloroplatinate ion dissolved in 1L of distilled water (pure water).
  3. A watershed got transformed from rural to urban over a period of time. The effect of urbanization on storm run-off hydrograph from the watershed is to (Civil Engg.)
    1. decrease the volume of run-off
    2. increase the time to peak discharge
    3. decrease the time base
    4. decrease the peak discharge

    Answer: Option  C.
    Urbanization will cause effective discharge of storm water by proper designed drainage path, hence time base of hydrograph will reduce.
  4. Stokes theorem connects (Mechnical Engg.)
    1. a line integral and a surface integral
    2. a surface integral and a volume integral
    3. a line integral and a volume integral
    4. gradient of a function and its surface integral

    Answer: Option  A.
    Stokes statement-
    Let, S be a piecewise smooth open surface bounded by a piecewise smooth simple closed bounded by a piecewise smooth simple closed curve.
    (x, y, z) can be continuous vector function which has continuous first partial derivatives in a region of space which contains S in its interior, then;
    cF· dr= ∫s∫ curl F.dS
    Hence, Stokes theorem connects a line integral and a surface integral.
  5. If a system is in equilibrium and the position of the system depends upon many independent variables, the principle of virtual work states that the partial derivatives of its total potential energy with respect to eaeh of the independent variable must be (Mechnical Engg.)
    1. -1.0
    2. Zero
    3. 1.0
    4. Infinite

    Answer:  Option  B.
    The given statement is the principle of virtual work according to which the partial derivative of total potential energy with respect to each independent variable is zero.
  6. An axial residual compressive stress due to a manufacturing process is present on the outer surface of a rotating shaft subjected to bending. Under a given bending-load, the fatigue life of the shaft in the presence of the residual compressive stress is(Mechnical Engg.)
    1. decreased
    2. increased or decreased, depending on the external bending load
    3. neither decreased nor increased
    4. Increased

    Answer: Option  D.
    The fatigue life of a rotating shaft subjected to bending will always be increased under residual axial compressive stress as it will reduce the tensile stress on fibre in one revolution and will increase the compressive stress during half revolution on same fibre
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