Heat and Mass Transfer A composite slab has two layers of different materials with thermal conductivities k₁ and k₂. If each layer has the same thickness, then the equivalent thermal conductivity of the slab will be 2 k₁ k₂/ (k₁ + k₂) k₁ k₂ (k₁ + k₂)/ k₁ k₂ (k₁ + k₂) 2 k₁ k₂/ (k₁ + k₂) k₁ k₂ (k₁ + k₂)/ k₁ k₂ (k₁ + k₂) ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The heat transfer takes place according to First law of thermodynamics Kirchhoff's law Second law of thermodynamics Zeroth law of thermodynamics First law of thermodynamics Kirchhoff's law Second law of thermodynamics Zeroth law of thermodynamics ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Moisture would find its way into insulation by vapour pressure unless it is prevented by High thickness of insulation Less thermal conductivity insulator A vapour seal High vapour pressure High thickness of insulation Less thermal conductivity insulator A vapour seal High vapour pressure 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 Opaque body Black body Grey body White body Opaque body Black body Grey body ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer According to Prevost theory of heat exchange Heat transfer in most of the cases takes place by combination of conduction, convection and radiation Heat transfer by radiation requires no medium All bodies above absolute zero emit radiation It is impossible to transfer heat from low temperature source to t high temperature source Heat transfer in most of the cases takes place by combination of conduction, convection and radiation Heat transfer by radiation requires no medium All bodies above absolute zero emit radiation It is impossible to transfer heat from low temperature source to t high temperature source ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer In case of liquids and gases, the heat transfer takes place according to Radiation None of these Conduction Convection Radiation None of these Conduction Convection ANSWER DOWNLOAD EXAMIANS APP
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