Heat and Mass Transfer In a heat exchanger with one fluid evaporating or condensing, the surface area required is least in Parallel flow Cross flow Counter flow All of these Parallel flow Cross flow Counter flow All of these ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The heat transfer from a hot body to a cold body is directly proportional to the surface area and difference of temperatures between the two bodies. This statement is called Newton's law of heating First law of thermodynamics Newton's law of cooling Stefan's law Newton's law of heating First law of thermodynamics Newton's law of cooling Stefan's law ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Depending on the radiating properties, a body will be black when (Where a = absorptivity, p = reflectivity, X = transmissivity.) P = 0, x = 1 and a = 0 P= 1, T = 0 and a = 0 P = 0, x = 0 and a = 1 X = 0, a + p = 0 P = 0, x = 1 and a = 0 P= 1, T = 0 and a = 0 P = 0, x = 0 and a = 1 X = 0, a + p = 0 ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The thermal diffusivities for gases are generally More than those for solids Dependent on the viscosity Less than those for liquids More than those for liquids More than those for solids Dependent on the viscosity Less than those for liquids More than those for liquids ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The logarithmic mean temperature difference (tm) is given by (where Δt1 and Δt2 are temperature differences between the hot and cold fluids at entrance and exit) tm = loge (Δt1/Δt2)/ (Δt1 - Δt2) tm = loge (Δt1 - Δt2)/ Δt1/Δt2 tm = tm = (Δt1 - Δt2) loge (Δt1/Δt2) tm = (Δt1 - Δt2)/ loge (Δt1/Δt2) tm = loge (Δt1/Δt2)/ (Δt1 - Δt2) tm = loge (Δt1 - Δt2)/ Δt1/Δt2 tm = tm = (Δt1 - Δt2) loge (Δt1/Δt2) tm = (Δt1 - Δt2)/ loge (Δt1/Δt2) ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Thermal diffusivity is 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 Function of temperature ANSWER DOWNLOAD EXAMIANS APP
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