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 k₁ k₂ 2 k₁ k₂/ (k₁ + k₂) (k₁ + k₂) (k₁ + k₂)/ k₁ k₂ k₁ k₂ 2 k₁ k₂/ (k₁ + k₂) (k₁ + k₂) (k₁ + k₂)/ k₁ k₂ 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 Grey body White body Black body Opaque body Grey body White body Black body Opaque body ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Fourier's law of heat conduction is (where Q = Amount of heat flow through the body in unit time, A = Surface area of heat flow, taken at right angles to the direction of heat flow, dT = Temperature difference on the two faces of the body, dx = Thickness of the body, through which the heat flows, taken along the direction of heat flow, and k = Thermal conductivity of the body) k. A. (dT/dx) k. A. (dx/dT) k. (dT/dx) k. (dx/dT) k. A. (dT/dx) k. A. (dx/dT) k. (dT/dx) k. (dx/dT) ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer A cube at high temperature is immersed in a constant temperature bath. It loses heat from its top, bottom and side surfaces with heat transfer coefficients of h₁, h₂ and h₃ respectively. The average heat transfer coefficient for the cube is 1/h₁ + 1/h₂ + 1/h₃ None of these (h₁.h₂.h₃)1/3 h₁ + h₂ + h₃ 1/h₁ + 1/h₂ + 1/h₃ None of these (h₁.h₂.h₃)1/3 h₁ + h₂ + h₃ ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer A designer chooses the values of fluid flow rates and specific heats in such a manner that the heat capacities of the two fluids are equal. A hot fluid enters the counter flow heat exchanger at 100°C and leaves at 60°C. A cold fluid enters the heat exchanger at 40°C. The mean temperature difference between the two fluids is 20°C 60°C 66.7°C 40°C 20°C 60°C 66.7°C 40°C ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Heat transfer takes place as per First law of thermodynamic Second law of the thermodynamics Zeroth law of thermodynamics Kirchoff's law First law of thermodynamic Second law of the thermodynamics Zeroth law of thermodynamics Kirchoff's law ANSWER DOWNLOAD EXAMIANS APP
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