MCQOPTIONS
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MCQOPTIONS
This section includes 5 Mcqs, each offering curated multiple-choice questions to sharpen your Materials Science knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
Diffusion through grain boundaries is very fast and is called short-circuit diffusion.Assertion: Their contribution to overall diffusion is negligible. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 2. |
Predeposition and drive-in diffusion are two heat treatments used in the manufacture of integrated circuits.Assertion: Predepostion is carried at a higher temperature than drive-in diffusion. |
| A. | True |
| B. | False |
| Answer» C. | |
| 3. |
If C is the concentration of the diffusing species at distance x from the source and time t, then according to Fick s second law (assuming diffusion coefficient, D is constant): |
| A. | C/ x = D.( C/ t) |
| B. | C/ t = D.( <sup>2</sup>C/ x<sup>2</sup>) |
| C. | C/ x = D.( <sup>2</sup>C/ t<sup>2</sup>) |
| D. | C/ t = D.( C/ x) |
| Answer» C. C/ x = D.( <sup>2</sup>C/ t<sup>2</sup>) | |
| 4. |
The expression J = M/(A.t), where J, M, A, & t are diffusion flux, mass of diffusing species, cross sectional area, and time respectively is: |
| A. | incorrect |
| B. | valid for steady-state diffusion only |
| C. | valid for non steady state diffusion only |
| D. | valid for both steady and non steady state diffusion |
| Answer» E. | |
| 5. |
In steady state diffusion, which of the following remain unchanged with time? |
| A. | Concentration at source |
| B. | Concentration at sink |
| C. | Concentration profile |
| D. | All of mentioned |
| Answer» E. | |