Heat and Mass Transfer The heat transfer takes place according to Kirchhoff's law Second law of thermodynamics First law of thermodynamics Zeroth law of thermodynamics Kirchhoff's law Second law of thermodynamics First law of thermodynamics Zeroth law of thermodynamics ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Two long parallel surfaces each of emissivity 0.7 are maintained at different temperatures and accordingly have radiation heat exchange between them. It is desired to reduce 75% of the radiant heat transfer by inserting thin parallel shields of emissivity 1 on both sides. The number of shields should be Four Three One Two Four Three One Two ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Depending on the radiating properties, a body will be white when(Where a = absorptivity, p = reflectivity, x = transmissivity) X = 0, a + p = 1 P = 0, x = 0 and a = 1 P=1, T = 0 and a = 0 P = 0, x = 1 and a = 0 X = 0, a + p = 1 P = 0, x = 0 and a = 1 P=1, T = 0 and a = 0 P = 0, x = 1 and a = 0 ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The emissivity for a black body is 0.75 1 0.5 0.75 1 0.5 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 = 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) ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Upto the critical radius of insulation, Added insulation will decrease heat loss Convective heat loss will be less than conductive heat loss Added insulation will increase heat loss Heat flux will decrease Added insulation will decrease heat loss Convective heat loss will be less than conductive heat loss Added insulation will increase heat loss Heat flux will decrease ANSWER DOWNLOAD EXAMIANS APP
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