Heat and Mass Transfer The heat transfer by conduction through a thick sphere is given by Q = 6πkr1 r2 (T1 - T2)/ (r2 - r1) Q = 4πkr1 r2 (T1 - T2)/ (r2 - r1) Q = 2πkr1 r2 (T1 - T2)/ (r2 - r1) Q = 8πkr1 r2 (T1 - T2)/ (r2 - r1) Q = 6πkr1 r2 (T1 - T2)/ (r2 - r1) Q = 4πkr1 r2 (T1 - T2)/ (r2 - r1) Q = 2πkr1 r2 (T1 - T2)/ (r2 - r1) Q = 8πkr1 r2 (T1 - T2)/ (r2 - r1) ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer An electric cable of aluminium conductor (k = 240 W/mK) is to be insulated with rubber (k = 0.15 W/mK). The cable is to be located in air (h = 6 W/m²). The critical thickness of insulation will be 40 mm 160 mm 800 mm 25 mm 40 mm 160 mm 800 mm 25 mm ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Thermal conductivity of air with rise in temperature May increase or decrease depending on temperature Increases Decreases Remain constant May increase or decrease depending on temperature Increases Decreases Remain constant ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer A steam pipe is to be lined with two layers of insulating materials of different thermal conductivities. For the minimum heat transfer, The better insulation must be put outside One should take into account the steam temperature before deciding as to which insulation is put where One could place either insulation on either side The better insulation must be put inside The better insulation must be put outside One should take into account the steam temperature before deciding as to which insulation is put where One could place either insulation on either side The better insulation must be put inside ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The ratio of the emissive power and absorptive power of all bodies is the same and is equal to the emissive power of a perfectly black body. This statement is known as Planck's law Stefan's law Wien's law Kirchhoff's law Planck's law Stefan's law Wien's law Kirchhoff's law ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Pick up the wrong case. Heat flowing from one side to other depends directly on Face area Time Thickness Temperature difference Face area Time Thickness Temperature difference ANSWER DOWNLOAD EXAMIANS APP
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