A. P and Q
B. P and R
C. P and S
D. R and S
Correct Answer: P and S ✔
Last Updated: March 03, 2019
Related MCQs
- Air is to be heated by condensing steam. Two heat exchangers are available (i) a shell and tube heat exchanger and (ii) a finned tube heat exchanger. Tube side heat transfer area are equal in both the cases. The recommended arrangement is__________?
- Heat exchanger tubes are never made of__________?
- The variation of thermal conductivity of a metal with temperature is often correlated using an expression of the form K = K0 + at, where, K is the thermal conductivity and T is the temperature (in °K). The units of ‘a’ in SI system will be__________?
- Colburn analogy is applicable for the value of Prandtl number from__________?
- For what value of Prandtl number, the Col-burn analogy is valid ?
- The thermal efficiency of a reversible heat engine operating between two given thermal reservoirs is 0.4. The device is used either as a refrigerator or as a heat pump between the same reservoirs. Then the coefficient of performance as a refrigerator (COP)R and the co-efficient of performance as a heat pump (COP)HP are __________?
- Heat transfer rate per unit area is called__________?
- Tube pitch is the __________ of tube diameters and the clearances?
- A black body when hot, emits heat radiation of __________ wavelengths?
- With increase in temperature, the thermal conductivity of non-metallic amorphous solids__________?
- Which of the following parameters is increased by use of finned tube in a multipass shell and tube heat exchanger ?
- Value of Nusselt number [Nu = (hD/k)] for the heat transfer by conduction from a droplet or a spherical particle to a surrounding stagnant film is__________?
- The main purpose of providing fins on heat transfer surface is to increase the__________?
- When vaporisation takes place through a blanketting film of gas, the phenomenon is termed as __________ boiling?
- The left face of a one dimensional slab of thickness 0.2 m is maintained at 80°C and the right face is exposed to air at 30°C. The thermal conductivity of the slab is 1.2 W/m.K and the heat transfer co-efficient from the right face is 10 W/m2.K. At steady state, the temperature of the right face in °C is__________?
- Agitated film evaporator is suitable for concentrating __________ liquids?
- Kirchoff’s law is applicable to__________?
- The Dittus-Boelter equation for convective heat transfer [(i.e. h = 0.023 (K/D) (Re)0.8 (Pr)0.4] cannot be used for__________?
- The radiation heat flux from a heating element at a temperature of 800°C, in a furnace maintained at 300°C is 8 kW/m2. The flux, when the element temperature is increased to 1000°C for the same furnace temperature is__________?
- A composite flat wall of a furnace is made of two materials ‘A’ and ‘B’. The thermal conductivity of ‘A’ is twice of that of material ‘B’, while the thickness of layer of ‘A’ is half that of B. If the temperature at the two sides of the wall are 400 and 1200°K, then the temperature drop (in °K) across the layer of material ‘A’ is__________?
- In forced convection, the heat transfer depends on __________?
- Kg of liquid evaporated per hour in an evaporator is defined as its__________?
- In SI units, fouling factor is expressed in __________?
- Radiation heat losses from satisfactorily insulated high pressure boiler may be about __________ percent?
- In the free convection regime of pool boiling, the heat flux is proportional to__________?
- Prandtl number is the ratio of__________?
- Prandtl number is given by__________?
- Trap is used to remove __________ from steam pipe lines?
- Wavelength corresponding to the maximum energy is inversely proportional to the absolute temperature. This is __________ law?
- Economy of a multiple effect evaporator depends upon the __________?
- A wall has two layers of materials A and B; each made of a different material. Both the layers have the same thickness. The thermal conductivity of material A is twice that of B. Under the equilibrium, the temperature difference across the wall is 36°C. The temperature difference across the layer A is __________ °C?
- Temperature profile in steady state heat transfer is__________?
- Maximum water velocity in tubes of a 1-2 shell and tube heat exchanger may be around __________ metres/second?
- A tank painted with which of the following coloured paints, would heat up maximum by radiation from sun ?
- Three materials A, B and C of equal thickness and of thermal conductivity of 20, 40 & 60 kcal/hr. m. °C respectively are joined together. The temperature outside of A and C are 30°C and 100°C respectively. The interface between B and C will be at a temperature of __________ °C?
- 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__________?
- Evaporation by thermo compression results in the __________?
- Use of transverse baffles in a shell and tube heat exchanger is done to increase the__________?
- Which of the following situations can be approximated to a steady state heat transfer system ?
- Heat transfer by __________ may not necessarily require the presence of a medium?
- Nusselt number is the ratio of the __________?
- Prandtl number is the reciprocal of__________?
- For a multipass shell and tube heat exchanger, the LMTD correction factor is always__________?
- Thermal conductivity of a gas at low density, __________ with increase in temperature ?
- The interchange factor for radiation heat transfer from surface ‘x’ to surface ‘y’ in case of an infinite parallel planes with emissivities εx & εy is given by__________?
- With increase in temperature, the thermal conductivity of a gas __________?
- Which area is used in case of heat flow by conduction through a cylinder ?
- The rate of emission of radiation by a body does not depend upon the__________?
- In a cooling tower, water becomes cool by__________?
- Out of the following four assumptions used in the derivation of the equation for LMTD [LMTD = (Δt1 – Δt2)/ln(Δt1/Δt2)], which one is subject to the largest deviation in practice ?
- What is the logarithmic mean of r1 and r2 ?