Q. The thermal radiation emitted by a body is proportional to Tⁿ, where T is its absolute temperature. The value of 'n' is exactly 4 for

View solution

Q. It is not preferable to use superheated steam in evaporators, because of its very

View solution

Q. It is desired to concentrate a 20% salt solution (20 kg of salt in 100 kg of solution) to a 30% salt solution in an evaporator. Consider a feed of 300 kg/min at 30°C. The boiling point of the solution is 110°C, the latent heat of vaporisation is 2100 kJ/kg and the specific heat of the solution is 4 kJ/kg.K. The rate at which the heat has to be supplied in (kJ/min) to the evaporator is

View solution

Q. LMTD for counterflow and prallel flow heat exchanger will be the same, when the

View solution

Q. For large heat transfer area requirement, shell and tube heat exchanger is preferred, because it

View solution

Q. Heat flux increases with temperature drop beyond the Leiden frost point in the plot of heat flux vs. temperature drop for a boiling liquid, because

View solution

Q. Resistance to heat flow by conduction is proportional to (where, t & ρ are thickness & density of the material respectively and A = area normal to the direction of heat flow. )

View solution

Q. Temperature profile in steady state heat transfer is

View solution

Q. Which area is used in case of heat flow by conduction through a cylinder ?

View solution

Q. Heat transfer by conduction results due to the transfer of free electrons, kinetic energy & vibrational energy from one molecule to another. Conduction heat transfer can not take place

View solution

Q. The dimensionless group in mass transfer that is equivalent to Prandtl number in heat transfer is

View solution

Q. Finned tube heat exchangers

View solution

Q. The absorptivity of a grey body at a given temperature __________ with increasing wavelength of radiation.

View solution

Q. A perfect black body is a perfect __________ of radiation.

View solution

Q. In case of parallel flow heat exchanger, the lowest temperature theoretically attainable by the hot fluid is __________ the outlet temperature of the cold fluid.

View solution

Q. An equipment which converts the latent or sensible heat of one fluid into the latent heat of vaporisation of another, is called a

View solution

Q. Which of the following is directly concerned with the heat transfer ?

View solution

Q. Pick out the wrong statement:

View solution

Q. Heat transfer by __________ may not necessarily require the presence of a medium.

View solution

Q. Pick out the correct statement.

View solution