A. 1 kcal/hr.m.°C is equal to 1 BTU/hr. ft.°F
B. In steady state heat conduction, the only property of the substance which determines the temperature distribution, is the thermal conductivity
C. In unsteady state heat conduction, heat flows in the direction of temperature rise
D. In heat transfer by forced convection, Grashoff number is very important
Related Mcqs:
- Pick out the correct statement ?
A. Higher is the temperature of the radiating body, higher is the wavelength of radiation
B. Logarithmic mean area is used for calculating the heat flow rate through a thick walled
cylinder
C. The wavelength corresponding to maximum mono-chromatic emissive power increases with
rise in temperature
D. Solid angle subtended by the finite surface at the radiating element is called the angle of
incidence - Pick out the correct equation ?
A. jH = (St)(Pr)2/3 = f/2
B. jH = (St)(Pr)1/3 = f/2
C. jH = (St)2/3(Pr) = f/2
D. jH = (St)1/3(Pr) = f/2 - Pick out the wrong statement ?
A. In drying a solid containing moisture above the critical moisture content the number of degrees of freedom is 2
B. Sherwood number in mass transfer corresponds to Nusselt number in heat transfer and Schmidt number to Prandtl number
C. Forced convection is relatively more effective in increasing the rate of mass transfer, if Schmidt number is larger
D. Hot gases at moderate pressure are usually in the shell side of shell and tube heat exchangers. At higher pressure, however, it is customary to put gas in the tube side - Pick out the wrong statement?
A. In process heat exchangers, saturated steam is preferred over the superheated steam
B. The maximum is the emissive power of a surface at a temperature T1 occurs at a wavelength
of λ1. If the surface temperature is halved, the maximum in the emissive power would occur at
a wavelength of 0.5 λ1
C. When a vertical plate is heated in infinite air environmental under natural convection
conditions, the velocity profile in air, normal to the plate, exhibits a maximum
D. A body at 925 K emits an energy of 1.42 x 1011ζW/m2 (ζ is the Stefan-Boltzmann constant) in
the wavelength band between 3 μm to 4 μm. The fraction of this energy in the total energy
emitted over the entire wavelength range is equal to emissivity - Pick out the wrong statement ?
A. The controlling resistance in case of heating of air by condensing steam is in the air fil
B. The log mean temperature difference (LMTD) for counter flow and parallel flow can be theoretically same when any one of the fluids (hot or cold fluid) passes through the heat exchanger at constant temperature
C. In case of a 1 – 2 shell and tube heat exchanger, the LMTD correction factor value increases
sharply, when a temperature cross occurs
D. Phase change in case of a pure fluid at a given pressure from liquid to vapor or vice-versa occurs at saturation temperature - Pick out the wrong statement?
A. Orifice baffles are never used in a shell and tube heat exchanger
B. Pressure drop on the shell side of a heat exchanger depends upon tube pitch also
C. In a horizontal tube evaporator, surface blanketing by air is avoided
D. Split ring type and pull through type floating heads are two commonly used floating heads is
heat exchangers - Pick out the wrong statement?
A. Reciprocal of the resistance to heat flow is called thermal conductance
B. Unit of thermal conductance is W/°K
C. Thermal conductance of a wall of thickness ‘L’, thermal conductivity ‘k’ and heat flow area ‘A’ is kL/A
D. None of these - Pick out the wrong statement?
A. Swenson-Walker crystalliser is a batch crystalliser
B. Super saturation of the solution is the driving potential for a crystal growth
C. The liquor left after the removal of crystals from a solution is called mother liquor
D. The first stage of crystal formation is called nucleation - Pick out the wrong statement ?
A. Heat transfer by radiation cannot occur across an absolute volume
B. In case of a shell and tube heat exchanger, the pressure drop through the shell is proportional to the number of times the fluid crosses the bundle between baffles
C. Propagation velocity for travel of heat radiation through vacuum is equal to the velocity of the light
D. The amount of heat involved in the condensation or vaporisation of 1 kg of a fluid is the same - Pick out the wrong statement ?
A. Superheated steam is preferably not used for process heating because of its low heat transfer film co-efficient
B. In a shell and tube heat exchanger, the shell pressure drop is maximum for orifice baffles
C. S.I. unit of fouling factor is Watt/m2.°K
D. Longitudinal fins are used in extended surface heat exchangers, when the direction of fluid flow is parallel to the axis of the tube
