Question No : 1
All radiations in a black body are
Question No : 2
According to Stefan Boltzmann law, the total radiation from a black body per second per unit area is directly proportional to the
Question No : 3
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)
Question No : 4
According to Newton's law of cooling, the heat transfer from a hot body to a cold body is
Question No : 5
When absorptivity (α) = 1, reflectivity (ρ) = 0 and transmissivity (τ) = 0, then the body is said to be a
Question No : 6
In convection heat transfer from hot flue gases to water tube, even though flow may be turbulent, a laminar flow region (boundary layer of film) exists close to the tube. The heat transfer through this film takes place by
Question No : 7
The ratio of Nusselt number and the product of Reynold's number and Prandtl number is equal to