MCQOPTIONS
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MCQOPTIONS
This section includes 12 Mcqs, each offering curated multiple-choice questions to sharpen your Mechanical Metallurgy knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
The number of dislocation of the same sign in the vertical plane is in stable equilibrium. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 2. |
Two opposite sign dislocations are separated by 100 nm in iron with grain size 4 mm. Determine the attractive force and total force on the two dislocations? Shear modulus of iron is 80 GPa, and the lattice parameter is 2.86 Ao |
| A. | 312.59*10<sup>-3</sup> N/m, 1.25*10<sup>-9</sup> N |
| B. | 112.59*10<sup>-3</sup> N/m, 8.25*10<sup>-9</sup> N |
| C. | 312.59*10<sup>-9</sup> N/m, 1.25*10<sup>-3</sup> N |
| D. | 312.59 N/m, 1.25 N |
| Answer» B. 112.59*10<sup>-3</sup> N/m, 8.25*10<sup>-9</sup> N | |
| 3. |
The force is _____________ between 2 parallel screw dislocation and ____________ for antiparallel screw dislocation. |
| A. | attractive, repulsive |
| B. | repulsive, attractive |
| C. | attractive, attractive |
| D. | repulsive, repulsive |
| Answer» B. repulsive, attractive | |
| 4. |
Dislocation of opposite sign on the same plane will ___________ each other. |
| A. | attract |
| B. | repeal |
| C. | not interact with |
| D. | have a stable equilibrium with |
| Answer» B. repeal | |
| 5. |
Dislocation of same sign on the same plane will ___________ each other. |
| A. | attract |
| B. | repeal |
| C. | not interact with |
| D. | have stable equilibrium with |
| Answer» C. not interact with | |
| 6. |
Shear stress required to bend a dislocation of radius R and burger vector b is P. What will be shear stress needed to turn a dislocation of radius 2R and burger s vector 2b to bend the dislocation? |
| A. | P |
| B. | 2P |
| C. | 4P |
| D. | 16P |
| Answer» B. 2P | |
| 7. |
Free energy of crystal __________ by introduction of dislocation in the structure. |
| A. | increases |
| B. | decreases |
| C. | remain unchanged |
| D. | sometimes increases and sometimes decreases |
| Answer» B. decreases | |
| 8. |
The strain energy of dislocation for each atom is in order of few __________ |
| A. | eV |
| B. | mJ |
| C. | J |
| D. | V |
| Answer» B. mJ | |
| 9. |
For a dislocation with burger s vector equal to b, the strain energy per unit length is X. What will be the strain energy with burger s vector is equal to 3b? |
| A. | X |
| B. | 3X |
| C. | 9X |
| D. | 3X |
| Answer» D. 3X | |
| 10. |
The ratio of strain energy of edge dislocation to screw dislocation is equal to ___________Where v is poison s ratio, and b is the Burger s vector. |
| A. | 1/(1-v) |
| B. | v |
| C. | vb |
| D. | b |
| Answer» B. v | |
| 11. |
One screw and one edge dislocation will have same strain energy if the burger vector is equal. |
| A. | True |
| B. | False |
| Answer» C. | |
| 12. |
In case of screw dislocation, the stresses around dislocation are ________ |
| A. | tensile in nature for right-hand screw dislocation |
| B. | tensile in nature for left-hand screw dislocation |
| C. | compressive in nature for right-hand screw dislocation |
| D. | there are no tensile or compressive normal stresses |
| Answer» E. | |