Heat and Mass Transfer
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

Conduction
Both convection and conduction
Convection
Radiation

ANSWER DOWNLOAD EXAMIANS APP

Heat and Mass Transfer
According of Kirchhoff's law

Emissive power and absorptivity are constant for all bodies
Radiant heat is proportional to fourth power of absolute temperature
Ratio of emissive power to absorptive power for all bodies is same and is equal to the emissive power of a perfectly black body
Emissive power depends on temperature

ANSWER DOWNLOAD EXAMIANS APP