Q. A sheet of Fe 1.0 mm thick is exposed to an oxidizing gas on one side and a deoxidizing gas on the other at 725°C. After reaching steady state, the Fe membrane is exposed to room temperature, and the C concentrations at each side of the membrane are 0.012 and 0.075 wt%. Calculate the diffusion coefficient (m²/sec) if the diffusion flux is 1.4×10⁻⁸kg/m²-sec.

View solution

Q. At which condition molar flux with respect to a stationary observer and with respect to an observer moving with molar average velocity?

View solution

Q. Which among the following is the statement of the ‘Fick’s Law’?

View solution

Q. The gas A diffuses through non-diffusing B from point 1 to point 2. The total pressure is 2atm and yᴀ₁=0.1 and yᴀ₂=0.Then the ratio (dPᴀ/dz)1/(dPᴀ/dz)2 is

View solution

Q. In industries titanium is hardened through diffusion of carbon. The concentration of carbon at 1mm into the surface of the titanium slab is 0.25kg/m³ and at 3mm the concentration is 0.68kg/m³. The rate at which the carbon is entering into its surface is 1.27*10⁻⁹kg/m².s. Calculate the value of diffusion coefficient of carbon.

View solution

Q. The mass transfer by convection can take place under how many conditions?

View solution

Q. Lewis number is given by

View solution

Q. Prandtl number is given by

View solution

Q. Schmidt number is given by

View solution

Q. Sherwood number is given by

View solution

Q. The solution for velocity, concentration and temperature boundary layers will be same if

View solution

Q. Convective mass transfer involves the transportation of material between a boundary surface and a moving fluid or between two immiscible fluids. It is prescribed by the relation

View solution

Q. Which number forms the connecting link between the velocity and temperature profiles?

View solution

Q. Which number forms the connecting link between the velocity and concentration profiles?

View solution

Q. Which number forms the connecting link between the temperature and concentration profiles?

View solution

Q. What is the value of emissivity for polished aluminum?

View solution

Q. Which one is having highest emissivity?

View solution

Q. What is the value of emissivity for polished copper?

View solution

Q. What is the value of emissivity for tarnished copper?

View solution

Q. Which one is having the lowest emissivity?

View solution