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 = 2.3 log (r₂/r₁)/[2πlk (T₁ - T₂)] Q = = 2πlk/2.3 (T₁ - T₂) log (r₂/r₁) Q = [2π (T₁ - T₂)]/2.3 lk log (r₂/r₁) Q = [2πlk (T₁ - T₂)]/2.3 log (r₂/r₁) Q = 2.3 log (r₂/r₁)/[2πlk (T₁ - T₂)] Q = = 2πlk/2.3 (T₁ - T₂) log (r₂/r₁) Q = [2π (T₁ - T₂)]/2.3 lk log (r₂/r₁) ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer When absorptivity (α) = 1, reflectivity (ρ) = 0 and transmissivity (τ) = 0, then the body is said to be a White body Black body Grey body Opaque body White body Black body Grey body Opaque body ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer In counter flow heat exchangers Both the fluids at exit are in their hottest state One fluid is in hottest state and other in coldest state at inlet Both the fluids at inlet (of heat exchanger where hot fluid enters) are in their coldest state Both the fluids at inlet are in their hottest state Both the fluids at exit are in their hottest state One fluid is in hottest state and other in coldest state at inlet Both the fluids at inlet (of heat exchanger where hot fluid enters) are in their coldest state Both the fluids at inlet are in their hottest state 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 = 0 and a = 1 X = 0, a + p = 0 P= 1, T = 0 and a = 0 P = 0, x = 1 and a = 0 P = 0, x = 0 and a = 1 X = 0, a + p = 0 P= 1, T = 0 and a = 0 P = 0, x = 1 and a = 0 ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Fourier's law of heat conduction gives the heat flow for One dimensional cases only Irregular surfaces Nonuniform temperature surfaces Two dimensional cases only One dimensional cases only Irregular surfaces Nonuniform temperature surfaces Two dimensional cases only ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The rate of heat flow through a body is Q = [kA (T₁ - T₂)]/x. The term x/kA is known as Thermal conductivity Thermal resistance Thermal coefficient None of these Thermal conductivity Thermal resistance Thermal coefficient None of these ANSWER DOWNLOAD EXAMIANS APP
EXAMIANS