MCQOPTIONS
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MCQOPTIONS
This section includes 11 Mcqs, each offering curated multiple-choice questions to sharpen your Phase Transformation knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
Radius of the new nuclei formed during heterogeneous nucleation depends on___________ |
| A. | T (undercooling) |
| B. | S( ) (Is a function of the wetting angle) |
| C. | A (surface area of parent particle) |
| D. | V (volume of parent particle) |
| Answer» B. S( ) (Is a function of the wetting angle) | |
| 2. |
The rate at which a transformation occurs will depend on the frequency with which atoms________ |
| A. | Reach the activated state |
| B. | Deviate from the activated stage |
| C. | Vibrate in the activated stage |
| D. | Rotate in the activated stage |
| Answer» B. Deviate from the activated stage | |
| 3. |
Gibbs free energy of a homogeneous nucleation is _____ |
| A. | Greater than heterogeneous nucleation |
| B. | Less than heterogeneous nucleation |
| C. | Greater than or equal to heterogeneous nucleation |
| D. | Less than or equal to heterogeneous nucleation |
| Answer» D. Less than or equal to heterogeneous nucleation | |
| 4. |
The magnitude of surface free energy of a spherical particle increases with radius. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 5. |
The magnitude of the contribution of volume free energy of a spherical particle increases with radius. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 6. |
During homogeneous for a spherical, the change in Gibbs free energy involve_______ |
| A. | Interfacial energy |
| B. | Volume free energy and surface free energy |
| C. | Rotational and Vibrational energy |
| D. | Surface free energy and vibrational energy |
| Answer» C. Rotational and Vibrational energy | |
| 7. |
Phase transformations in metals/alloys occur by _____ |
| A. | Random motion |
| B. | Explosion |
| C. | Rotation and vibration |
| D. | Nucleation and growth |
| Answer» E. | |
| 8. |
Homogeneous nucleation occurs only when liquid is undercooled by___________ |
| A. | Critical undercooling for nucleation |
| B. | Critical undercooling for growth |
| C. | Layered undercooling for nucleation |
| D. | Layered undercooling for growth |
| Answer» B. Critical undercooling for growth | |
| 9. |
Nucleation that takes place at the grain boundaries are known as___________ |
| A. | Heterogeneous nucleation |
| B. | Homogeneous nucleation |
| C. | Partial nucleation |
| D. | Mixed nucleation |
| Answer» B. Homogeneous nucleation | |
| 10. |
Which among the following condition should be satisfied by heterogeneous nucleation? |
| A. | Occurs spontaneously |
| B. | Doesn t have a preferential nucleation site |
| C. | Occurs randomly |
| D. | Occurs at preferential sites |
| Answer» E. | |
| 11. |
Which among the following condition should be satisfied by homogeneous nucleation? |
| A. | Occurs slowly |
| B. | Occurs at the preferential site |
| C. | Occurs in an orderly fashion |
| D. | Occurs randomly |
| Answer» E. | |