__ energy helps with molecular diffusion.

Thermal

Electrical

Internal

All of the above

0.2

0.25

0.4

1

0.2 atm

0.4 atm

0.6 atm

0.8 atm

The value of N flux of A under steady-state non-diffusing B with diffusing A is

0

Constant

Infinity

None of the above

1

2

3

None of the above

10 units

2.5 units

0.4 units

None of the above

Find the operation out of the following where diffusion of solids does not occur.

Adsorption

Leaching

Drying

Distillation

1

-1

2

-2

(i) Grashof number

(ii) Prandtl number

(iii) Nusselt number

Identify the correct answer out of the following

ii and iii

ii only

i and ii

i, ii and iii

True

False

**°**C to 25 **°**C in quiescent air. Approximate the bulb as a 50 mm diameter sphere. The approximate correlation for the convection coefficient is Nu = 0.60 (Gr Pr) 0.25, where the different parameters are evaluated at the mean film temperature. The characteristics length is the sphere's diameter.

4.71 W

5.71 W

6.71 W

7.71 W

**°**C whilst the ambient air is at 50 **°**C. Work out the ratios of the heat transfer coefficients.

0.136

1.316

2.136

3.136

**°**C temperature is immersed in a tank of water at 20 **°**C temperature. Determine the convective heat transfer coefficient.

458.32 W/m^2 K

558.32 W/m^2 K

658.32 W/m^2 K

758.32 W/m^2 K

For a steady-state diffusion of A through non-diffusing B, N flux of B =

0

1

2

**∞**

**°**C. If the pipe wall temperature is 295 **°**C, determine the rate of heat loss. At the mean temperature difference of 160 **°**C, the thermo-physical properties of air are

k = 3.64 * 10 -2 W/m K

v = 30.09 * 10 -6 m^2/s

P{r}= 0.682

Β = 1/160 + 273 = 2.31 * 10^(-3) per K

1156.5 W

1146.5 W

1136.5 W

1126.5 W

Quiz/Test Summary

Title:
Diffusion in Solids and Molecular Diffusion in Fluids

Questions:
15

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