A. 180
B. 970
C. 3.97
D. None of these
Correct Answer: 180 ✔
Last Updated: March 03, 2019
Related MCQs
- Baffle spacing __________?
- The local surface conductance for laminar film condensation on vertical surface is (where, t = film thickness) __________?
- The purpose of floating head in a heat exchanger is to__________?
- Mechanical recompression evaporation is used in the production of__________?
- The outlet temperature of cooling water in a heat exchanger is generally not allowed to exceed above 50°C in industrial practice mainly to avoid__________?
- The Fourier number (defined as a.t/L2) is used in the analysis of problem involving heat transfer by__________?
- Three solid objects of the same material and of equal mass-a sphere, a cylinder (length = diameter) and a cube are at 500°C initially. These are dropped in a quenching bath containing a large volume of cooling oil each attaining the bath temperature eventually. The time required for 90% change in temperature is the smallest for__________?
- Which of the following forced convection heat transfer equation accounts for the liquid viscosity effect for viscous liquids ?
- For condensation of pure vapors, if the heat transfer co-efficients in filmwise and drop-wise condensation are respectively hf and hd, then__________?
- Heat transfer in the laminar sub-layer in case of a liquid flowing through a pipe, is mostly by__________?
- __________ heat exchanger is the most suitable, when the temperature of shell side fluid is much higher than that of tube side?
- Evaporation of 1kg of water from a solution in a single effect evaporator requires about __________ kg of steam?
- Thermal conductivities of most of the liquids __________ with rise in temperature?
- The purpose of providing a ‘catchall’ in the vapor line of an evaporator is to__________?
- Removal of __________ heat is involved in the condensation of a vapor under saturated conditions?
- The energy radiated from a surface Q at absolute temperature T is related as__________?
- Absorptivity of a perfect black body is unity. Which of the following has maximum absorptivity ?
- Crystallisation of solids from a homogeneous solution is a/an __________ process?
- Steam condensate is recovered by steam traps and recycled for use as boiler feed water, because of its low__________?
- __________ paint has the maximum absorption coefficient ?
- Baffles are provided in heat exchangers to increase the__________?
- Prandtl and Reynold’s analogies are identical for Prandtl number value of__________?
- The rate of heat transfer through a pipe wall is given by, q = 2π k (Ti – T0)/ln (ri/r0). For cylinder of very thin wall, q can be approximated by__________?
- If a single tube pass heat exchanger is converted to two pass, then for the same flow rate, the pressure drop per unit length in tube side will __________?
- A measure of the extent to which viscous heating is important relative to the heat flow resulting from the impressed temperature difference is represented by the __________ number?
- Heat transfer efficiency leading of energy conservation in a heat exchanger can be achieved by__________?
- Which is the most suitable for the concert-ration of highly concentrated solution ?
- A hot liquid is kept in a big room. The logarithm of the numerical value of the temperature difference between the liquid and the room is plotted against time. The plot will be very nearly a/an__________?
- A hot body will radiate heat most rapidly, if its surface is__________?
- Prandtl number is the ratio of__________?
- Rate of heat transfer by vaporisation from pools of water is affected by the __________?
- The purpose of providing bleed points in the evaporator is to__________?
- With increase in temperature, the thermal conductivity of steel__________?
- In a shell and tube heat exchanger, the tube side heat transfer co-efficient just at the entrance of the tube is__________?
- Which of the following is the most controlling factor for the rate of bubble detachment from the hot solid surface ?
- Radiation heat transfer rates does not depend upon the__________?
- If all the conditions and dimensions are same, then the ratio of velocity through the tubes of a double pass heat exchanger to that through the single pass heat exchanger is__________?
- Which of the following is not concerned with the heat transfer ?
- __________ equation relates the thermal conductivity of a solid to its temperature ?
- Unsteady state heat conduction occurs, when__________?
- For specified tube outside diameter, higher BWG means higher__________?
- A long iron rod initially at a temperature of 20°C has one end dipped in boiling water (100°C) at time, t = 0. The curved surface of the rod is insulated so that heat conduction is one dimensional in the axial direction. The temperature at a distance 100 mm from the dipped end becomes 40°C at time, t = 200 s. The same temperature is achieved at a distance of 200 mm from the dipped end at time __________?
- Value of Prandtl number for water ranges from__________?
- For a fluid flowing in an annulus space, the wetted perimeter for heat transfer and pressure drop are__________?
- 1000 kg of wet solids are to be dried from 60% to 20% moisture (by weight). The mass of moisture removed in kg is__________?
- Dropwise condensation occurs on __________ surfaces?
- Conduction occurs in the buffer zone for a fluid flowing through a heated pipe, only when Prandtl number is__________?
- The type of liquor circulation system to be ‘ employed in evaporators (viz. natural or forced circulation) is determined mainly by the __________ of the liquid?
- For a given ambient air temperature with increase in the thickness of insulation of a hot cylindrical pipe, the rate of heat loss from the surface would ?
- In a backward feed multiple effect evaporator __________ ?
- The sum of reflectivity and absorptivity for an opaque body is equal to__________?