Test your basic knowledge |

Engineering Materials

Subject : engineering
Instructions:
  • Answer 50 questions in 15 minutes.
  • If you are not ready to take this test, you can study here.
  • Match each statement with the correct term.
  • Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.
1. Allows flow of electrons in one direction only (useful to convert alternating current to direct current) - Result: no net current flow






2. The ability of a material to transport heat - Atomic Perspective: Atomic vibrations and free electrons in hotter regions transport energy to cooler regions - Metals have the largest values






3. Sigma=ln(li/lo)






4. No appreciable plastic deformation. The crack propagates very fast; nearly perpendicular to applied stress. Cracks often propagate along specific crystal planes or boundaries.






5. Measures Hardness 1. psia = 500 x HB 2. MPa = 3.45 x HB






6. 1. Diamagnetic (Xm ~ 10^-5) - small and negative magnetic susceptibilities 2. Paramagnetic (Xm ~ 10^-4) - small and positive magnetic susceptibilities 3. Ferromagnetic - large magnetic susceptibilities 4. Ferrimagnetic (Xm as large as 10^6) - large m






7. Different orientation of cleavage planes in grains.






8. 1. Data for Pure Silicon - electrical conductivity increases with T - opposite to metals






9. They are used to assess properties of ceramics & glasses.






10. Hardness is the resistance of a material to deformation by indentation - Useful in quality control - Hardness can provide a qualitative assessment of strength - Hardness cannot be used to quantitatively infer strength or ductility.






11. Dimples on fracture surface correspond to microcavities that initiate crack formation.






12. Found in 26 metals and hundreds of alloys & compounds - Tc= critical temperature = termperature below which material is superconductive.






13. Emitted light is in phase






14. -> fluorescent light - electron transitions occur randomly - light waves are out of phase with each other.






15. Increase temperature - increase in interatomic separation - thermal expansion






16. Increase temperature - no increase in interatomic separation - no thermal expansion






17. Energy is stored as atomic vibrations - As temperature increases - the average energy of atomic vibrations increases.






18. A measure of the ease with which a B field can be induced inside a material.






19. These materials are relatively unaffected by magnetic fields.






20. 1. Tc= critical temperature- if T>Tc not superconducting 2. Jc= critical current density - if J>Jc not superconducting 3. Hc= critical magnetic field - if H > Hc not superconducting






21. 1. Metals: Thermal energy puts many electrons into a higher energy state. 2. Energy States: Nearby energy states are accessible by thermal fluctuations.






22. 1. Yield = ratio of functional chips to total # of chips - Most yield loss during wafer processing - b/c of complex 2. Reliability - No device has infinite lifetime. Statistical methods to predict expected lifetime - Failure mechanisms: Diffusion reg






23. The size of the material changes with a change in temperature - polymers have the largest values






24. These are liquid crystal polymers- not your normal "crystal" -Rigid - rod shaped molecules are aligned even in liquid form.

Warning: Invalid argument supplied for foreach() in /var/www/html/basicversity.com/show_quiz.php on line 183


25. Specular: light reflecting off a mirror (average) - Diffuse: light reflecting off a white wall (local)






26. The Magnetization of the material - and is essentially the dipole moment per unit volume. It is proportional to the applied field. Xm is the magnetic susceptibility.






27. Is reflected - absorbed - scattered - and/or transmitted: Io=It+Ia+Ir+Is






28. Undergo little or no plastic deformation.






29. 1. Ability of the material to absorb energy prior to fracture 2. Short term dynamic stressing - Car collisions - Bullets - Athletic equipment 3. This is different than toughness; energy necessary to push a crack (flaw) through a material 4. Useful in






30. Transformer cores require soft magnetic materials - which are easily magnetized and de-magnetized - and have high electrical resistivity - Energy losses in transformers could be minimized if their cores were fabricated such that the easy magnetizatio






31. If a material has ________ - then the field generated by those moments must be added to the induced field.






32. Becomes harder (more strain) to stretch (elongate)






33. Not ALL the light is refracted - SOME is reflected. Materials with a high index of refraction also have high reflectance - High R is bad for lens applications - since this leads to undesirable light losses or interference.






34. 1. General yielding occurs if flaw size a < a(critical) 2. Catastrophic fast fracture occurs if flaw size a > a(critical)






35. As the applied field (H) increases the magnetic domains change shape and size by movement of domain boundaries.






36. Growth of an oxide layer by the reaction of oxygen with the substrate - Provides dopant masking and device isolation - IC technology uses 1. Thermal grown oxidation (dry) 2. Wet Oxidation 3. Selective Oxidation






37. Because of ionic & covalent-type bonding.






38. With Increasing temperature - the saturation magnetization diminishes gradually and then abruptly drops to zero at Curie Temperature - Tc.






39. Ability to transmit a clear image - The image is clear.






40. heat flux = -(thermal conductivity)(temperature gradient) - Defines heat transfer by CONDUCTION

Warning: Invalid argument supplied for foreach() in /var/www/html/basicversity.com/show_quiz.php on line 183


41. Dramatic change in impact energy is associated with a change in fracture mode from brittle to ductile.






42. Digitalized data in the form of electrical signals are transferred to and recorded digitally on a magnetic medium (tape or disk) - This transference is accomplished by a recording system that consists of a read/write head - "write" or record data by






43. Small Coercivities - Used for electric motors - Example: commercial iron 99.95 Fe






44. # of thermally generated electrons = # of holes (broken bonds)






45. 1. Electron motions 2. The spins on electrons - Net atomic magnetic moment: sum of moments from all electrons.






46. These materials are "attracted" to magnetic fields.






47. 1. Imperfections increase resistivity - grain boundaries - dislocations - impurity atoms - vacancies 2. Resistivity - increases with temperature - wt% impurity - and %CW






48. Another optical property - Depends on the wavelength of the visible spectrum.






49. Wet: isotropic - under cut Dry: ansiotropic - directional






50. Metals are good conductors since their _______is only partially filled.