Heat and Mass Transfer The ratio of the emissive power and absorptive power of all bodies is the same and is equal to the emissive power of a perfectly black body. This statement is known as Stefan's law Kirchhoff's law Wien's law Planck's law Stefan's law Kirchhoff's law Wien's law Planck's law ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The thermal diffusivities for gases are generally Less than those for liquids Dependent on the viscosity More than those for solids More than those for liquids Less than those for liquids Dependent on the viscosity More than those for solids More than those for liquids ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer In a heat exchanger with one fluid evaporating or condensing, the surface area required is least in Cross flow Counter flow Parallel flow All of these Cross flow Counter flow Parallel flow All of these 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 = (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) tm = loge (Δt1/Δt2)/ (Δt1 - Δt2) tm = tm = (Δt1 - Δt2) loge (Δt1/Δt2) ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Conduction is a process of heat transfer None of these From one particle of the body to another by the actual motion of the heated particles From one particle of the body to another without the actual motion of the particles From a hot body to a cold body, in a straight line, without affecting the intervening medium None of these From one particle of the body to another by the actual motion of the heated particles From one particle of the body to another without the actual motion of the particles From a hot body to a cold body, in a straight line, without affecting the intervening medium ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Wien’s law states that the wave length corresponding to ________ is proportional to the absolute temperature. None of these Both (A) and (B) Minimum energy Maximum energy None of these Both (A) and (B) Minimum energy Maximum energy ANSWER DOWNLOAD EXAMIANS APP
EXAMIANS