Heat and Mass Transfer The amount of heat flow through a body by conduction is Directly proportional to the surface area of the body All of these Directly proportional to the temperature difference on the two faces of the body Dependent upon the material of the body Directly proportional to the surface area of the body All of these Directly proportional to the temperature difference on the two faces of the body Dependent upon the material of the 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. (dx/dT) k. (dT/dx) k. A. (dT/dx) k. A. (dx/dT) k. (dx/dT) k. (dT/dx) ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The value of Prandtl number for air is about 0.7 1.7 0.1 0.3 0.7 1.7 0.1 0.3 ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer According to Stefan Boltzmann law, ideal radiators emit radiant energy at a rate proportional to Square of temperature Fourth power of absolute temperature Fourth power of temperature Absolute temperature Square of temperature Fourth power of absolute temperature Fourth power of temperature Absolute temperature 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 = tm = (Δt1 - Δt2) loge (Δt1/Δt2) tm = loge (Δt1/Δt2)/ (Δt1 - Δt2) tm = (Δt1 - Δt2)/ loge (Δt1/Δt2) tm = loge (Δt1 - Δt2)/ Δt1/Δt2 tm = tm = (Δt1 - Δt2) loge (Δt1/Δt2) tm = loge (Δt1/Δt2)/ (Δt1 - Δt2) tm = (Δt1 - Δt2)/ loge (Δt1/Δt2) ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer According to Newton's law of cooling, the heat transfer from a hot body to a cold body is Both (A) and (B) Either (A) or (B) Directly proportional to the surface area Directly proportional to the difference of temperatures between the two bodies Both (A) and (B) Either (A) or (B) Directly proportional to the surface area Directly proportional to the difference of temperatures between the two bodies ANSWER DOWNLOAD EXAMIANS APP
EXAMIANS