Heat and Mass Transfer Depending on the radiating properties, body will be transparent when (Where a = absorptivity, p = reflectivity, x = transmissivity) P=1, x = 0, and a = 0 P = 0, x = 0 and a = 1 P = 0, x= 1, and a = 0 X = 0, a + p = 1 P=1, x = 0, and a = 0 P = 0, x = 0 and a = 1 P = 0, x= 1, and a = 0 X = 0, a + p = 1 ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The process of heat transfer from one particle of the fluid to another by the actual movement of the fluid particles caused by some mechanical means, is known as Radiation Forced convection Conduction Free convection Radiation Forced convection Conduction Free convection ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Thermal conductivity of water at 20°C is of the order of 0.42 0.51 0.1 0.23 0.42 0.51 0.1 0.23 ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The ratio of the energy absorbed by the body to total energy falling on it is called Absorptive power Emissivity Absorptivity Emissive power Absorptive power Emissivity Absorptivity Emissive power ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The heat transfer by conduction through a thick cylinder (Q) is given by (where T₁ = Higher temperature, T₂ = Lower temperature, r₁ = Inside radius, r₂ = Outside radius, l = Length of cylinder, and k = Thermal conductivity) Q = [2πlk (T₁ - T₂)]/2.3 log (r₂/r₁) Q = = 2πlk/2.3 (T₁ - T₂) log (r₂/r₁) Q = 2.3 log (r₂/r₁)/[2πlk (T₁ - T₂)] Q = [2π (T₁ - T₂)]/2.3 lk log (r₂/r₁) Q = [2πlk (T₁ - T₂)]/2.3 log (r₂/r₁) Q = = 2πlk/2.3 (T₁ - T₂) log (r₂/r₁) Q = 2.3 log (r₂/r₁)/[2πlk (T₁ - T₂)] Q = [2π (T₁ - T₂)]/2.3 lk log (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 800 mm 40 mm 160 mm 25 mm 800 mm 40 mm 160 mm 25 mm ANSWER DOWNLOAD EXAMIANS APP
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