Heat and Mass Transfer Planck’s law holds good for black bodies All of these all coloured bodies polished bodies black bodies All of these all coloured bodies polished bodies 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 Absorptivity of a body will be equal to its emissivity At all temperatures At critical temperature When system is under thermal equilibrium At one particular temperature At all temperatures At critical temperature When system is under thermal equilibrium At one particular 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 = (Δt1 - Δt2)/ loge (Δt1/Δt2) tm = tm = (Δt1 - Δt2) loge (Δt1/Δt2) tm = loge (Δt1 - Δt2)/ Δt1/Δt2 tm = loge (Δt1/Δt2)/ (Δt1 - Δt2) tm = (Δt1 - Δt2)/ loge (Δt1/Δt2) tm = tm = (Δt1 - Δt2) loge (Δt1/Δt2) tm = loge (Δt1 - Δt2)/ Δt1/Δt2 tm = loge (Δt1/Δt2)/ (Δt1 - Δt2) ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer An ordinary passenger aircraft requires a cooling system of capacity. 2 TR 10 TR 8 TR 4 TR 2 TR 10 TR 8 TR 4 TR ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer All radiations in a black body are Reflected Transmitted Absorbed Refracted Reflected Transmitted Absorbed Refracted ANSWER DOWNLOAD EXAMIANS APP
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