Heat and Mass Transfer Cork is a good insulator because it has Atoms colliding frequency Low density Free electrons Porous body Atoms colliding frequency Low density Free electrons Porous body ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer When α is absorptivity, ρ is reflectivity and τ is transmissivity, then for a diathermanous body, α = 0, ρ = 0 and τ = 1 α = 1, ρ = 0 and τ = 0 α + ρ = 1 and τ = 0 α = 0, ρ = 1 and τ = 0 α = 0, ρ = 0 and τ = 1 α = 1, ρ = 0 and τ = 0 α + ρ = 1 and τ = 0 α = 0, ρ = 1 and τ = 0 ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer If the energy radiated per second per sq. cm. of the surface for wave lengths lying between λ, and λ + dλ is represented by (eλ.dλ), then eλ is called Emissive power Absorptive power Emissivity None of these Emissive power Absorptive power Emissivity None of these ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Thermal conductivity of air with rise in temperature Increases Remain constant Decreases May increase or decrease depending on temperature Increases Remain constant Decreases May increase or decrease depending on temperature ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The time constant of a thermocouple is Determined by the time taken to reach 100°C from 0°C The time taken to attain 63.2% of the value of initial temperature difference The time taken to attain 50% of the value of initial temperature difference The time taken to attain the final temperature to be measured Determined by the time taken to reach 100°C from 0°C The time taken to attain 63.2% of the value of initial temperature difference The time taken to attain 50% of the value of initial temperature difference The time taken to attain the final temperature to be measured 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 One Four Three Two One Four Three Two ANSWER DOWNLOAD EXAMIANS APP
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