MCQOPTIONS
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MCQOPTIONS
This section includes 9 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 sensitivity of the fracture of the brittle solid to surface condition has been termed as the ____________ |
| A. | Bauschinger effect |
| B. | Doppler effect |
| C. | Joffe effect |
| D. | Polarity effect |
| Answer» D. Polarity effect | |
| 2. |
Griffith s theory for a thick plate predicts the fracture as_________ |
| A. | ( =( frac{2E }{(1-v) c)})^{1/2} ) |
| B. | ( =( frac{2E }{ c})^{1/2} ) |
| C. | ( =( frac{2E }{ c})^{1/2} ) |
| D. | ( =( frac{2E (1-v)}{ c})^{1/2} ) |
| Answer» B. ( =( frac{2E }{ c})^{1/2} ) | |
| 3. |
If the crack length inside the material is increased by 4 times. The fracture strength will ___________ |
| A. | decrease by 4 times |
| B. | decrease by 2 times |
| C. | increase by 4 times |
| D. | increase by 2 times |
| Answer» C. increase by 4 times | |
| 4. |
The statement of Griffith theory of brittle fracture says that A crack will propagate when the decrease in elastic strain energy is at least equal to the energy required to create the new surface . |
| A. | True |
| B. | false |
| Answer» B. false | |
| 5. |
Calculate the fracture stress of brittle material with the following properties.
|
| A. | 346.4 MPa |
| B. | 648.9 MPa |
| C. | 589.9 MPa |
| D. | 5898.8 MPa |
| Answer» B. 648.9 MPa | |
| 6. |
The fracture on the sharpest crack tip will be equal to (( frac{E _s}{4c})^{1/2} ) . |
| A. | True |
| B. | False |
| Answer» B. False | |
| 7. |
The maximum stress on the tip of the crack of length 2c and radius of curvature of the tip t is given as ____ |
| A. | <sub>max</sub>= ( [1+2( frac{c}{ t})^{1/2}] ) |
| B. | <sub>max</sub>= ( [1+( frac{c}{ t})^{1/2}] ) |
| C. | <sub>max</sub>= ( [2( frac{c}{ t})^{1/2}] ) |
| D. | <sub>max</sub>= ( [( frac{c}{ t})^{1/2}] ) |
| Answer» B. <sub>max</sub>= ( [1+( frac{c}{ t})^{1/2}] ) | |
| 8. |
Determine the cohesive strength of glass fibre, if E = 90 GPa, Surface energy = 1.2 Jm-1/2 and a0=0.18 nm? |
| A. | 29.5 GPa |
| B. | 10 GPa |
| C. | 24.5 GPa |
| D. | 150 MPa |
| Answer» D. 150 MPa | |
| 9. |
The theoretical cohesive strength of brittle material is approximately equal to ________ |
| A. | E |
| B. | E/2 |
| C. | E/ |
| D. | E/2 |
| Answer» D. E/2 | |