Heat Transfer

71. Black liquor generated during paper manufacture is concentrated in a

1. Single effect evaporator
2. Single effect evaporator followed by a crystalliser
3. Multiple effect evaporator
4. Multiple effect evaporators followed by a crystalliser

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72. Boiling of milk in an open vessel is an example of _________ boiling.

1. Film
2. Sub-cooled
3. Saturated nucleate
4. None of these

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73. Boiling point elevation for a strong and concentrated solution is found by Duhring's rule, which states that at the same pressure, the boiling point of a solution is a linear function of the _________ of pure water.

1. Boiling point
2. Dynamic viscosity
3. Kinematic viscosity
4. Density

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74. Boiling point elevation of a solution of NaOH

1. Increases rapidly with temperature rise
2. Is almost independent of temperature
3. Is almost independent of pressure
4. Both (B) and (C)

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75. Boiling point elevation of an ideal solution

1. Increases rapidly with temperature rise
2. Decreases rapidly with temperature rise
3. In independent of pressure
4. Both (B) and (C)

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76. Boiling point of a solution according to Duhring's rule is a linear function of the _________ of water.

1. Boiling point (at the same pressure)
2. Viscosity
3. Density
4. Thermal conductivity

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77. Bulk of the convective heat transfer resistance from a hot tube surface to the fluid flowing in it, is

1. In the central core of the fluid
2. Uniformly distributed throughout the fluid
3. Mainly confined to a thin film of fluid near the surface
4. None of these

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78. C_pμ/K is termed as the _________ number.

1. Grashoff
2. Nusselt
3. Prandtl
4. Stanton

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79. Choose the correct equation.

1. Nu = (Re) (Pr) (Gz)
2. Nu = (Re) (Pr) (St)
3. Nu = (Re) (Pr)
4. Nu = (Pr) (St)

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80. Choose the most important factor on which the heat conducted through a wall in a unit time will depend on?

1. Thickness of the wall
2. Area of the wall perpendicular to heat flow
3. Material of the wall
4. Temperature difference between the two surfaces of the wall

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