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 = 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) Q = [2πlk (T₁ - T₂)]/2.3 log (r₂/r₁) ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Heat transfer takes place as per Second law of the thermodynamics Kirchoff's law First law of thermodynamic Zeroth law of thermodynamics Second law of the thermodynamics Kirchoff's law First law of thermodynamic Zeroth law of thermodynamics ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Fouling factor is used None of these In case of Newtonian fluids When a liquid exchanges heat with a gas In heat exchanger design as a safety factor None of these In case of Newtonian fluids When a liquid exchanges heat with a gas In heat exchanger design as a safety factor ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer If the energy radiated per second per sq. cm. of the surface for wave lengths lying between λ, and λ + dλ is represented by (eλ.dλ), then eλ is called Emissivity Emissive power Absorptive power None of these Emissivity Emissive power Absorptive power None of these ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Depending on the radiating properties, a body will be white when(Where a = absorptivity, p = reflectivity, x = transmissivity) P=1, T = 0 and a = 0 X = 0, a + p = 1 P = 0, x = 1 and a = 0 P = 0, x = 0 and a = 1 P=1, T = 0 and a = 0 X = 0, a + p = 1 P = 0, x = 1 and a = 0 P = 0, x = 0 and a = 1 ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Cork is a good insulator because it has Free electrons Porous body Low density Atoms colliding frequency Free electrons Porous body Low density Atoms colliding frequency ANSWER DOWNLOAD EXAMIANS APP
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