Heat and Mass Transfer Depending on the radiating properties, body will be transparent when (Where a = absorptivity, p = reflectivity, x = transmissivity) X = 0, a + p = 1 P=1, x = 0, and a = 0 P = 0, x= 1, and a = 0 P = 0, x = 0 and a = 1 X = 0, a + p = 1 P=1, x = 0, and a = 0 P = 0, x= 1, and a = 0 P = 0, x = 0 and a = 1 ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Thermal diffusivity is Function of temperature A physical property of the material A dimensionless parameter Used as mathematical model Function of temperature A physical property of the material A dimensionless parameter Used as mathematical model ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer According to Stefan Boltzmann law, the total radiation from a black body per second per unit area is directly proportional to the Cube of the absolute temperature Square of the absolute temperature Absolute temperature Fourth power of the absolute temperature Cube of the absolute temperature Square of the absolute temperature Absolute temperature Fourth power of the absolute temperature 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 160 mm 800 mm 25 mm 40 mm 160 mm 800 mm 25 mm 40 mm ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The heat transfer by conduction through a thick sphere is given by Q = 4πkr1 r2 (T1 - T2)/ (r2 - r1) Q = 8πkr1 r2 (T1 - T2)/ (r2 - r1) Q = 6πkr1 r2 (T1 - T2)/ (r2 - r1) Q = 2πkr1 r2 (T1 - T2)/ (r2 - r1) Q = 4πkr1 r2 (T1 - T2)/ (r2 - r1) Q = 8πkr1 r2 (T1 - T2)/ (r2 - r1) Q = 6πkr1 r2 (T1 - T2)/ (r2 - r1) Q = 2πkr1 r2 (T1 - T2)/ (r2 - r1) ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Upto the critical radius of insulation, Added insulation will decrease heat loss Heat flux will decrease Added insulation will increase heat loss Convective heat loss will be less than conductive heat loss Added insulation will decrease heat loss Heat flux will decrease Added insulation will increase heat loss Convective heat loss will be less than conductive heat loss ANSWER DOWNLOAD EXAMIANS APP
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