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. Plastic means permanent! When a small load is applied - bonds stretch & planes shear. Then when the load is no longer applied - the planes are still sheared.






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






3. 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






4. Cracks propagate along grain boundaries.






5. Elastic means reversible! This is not a permanent deformation.






6. - Metals that exhibit high ductility - exhibit high toughness. Ceramics are very strong - but have low ductility and low toughness - Polymers are very ductile but are not generally very strong in shear (compared to metals and ceramics). They have low






7. To build a device - various thin metal or insulating films are grown on top of each other - Evaporation - MBE - Sputtering - CVD (ALD)






8. Without passing a current a continually varying magnetic field will cause a current to flow






9. Materials change size when temperature is changed






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






11. 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






12. Transmitted light distorts electron clouds - The velocity of light in a material is lower than in a vacuum - Adding large ions to glass decreases the speed of light in the glass - Light can be "bent" (or refracted) as it passes through a transparent






13. Cracks pass through grains - often along specific crystal planes.






14. Width of smallest feature obtainable on Si surface






15. 1. Ductility- % elongation - % reduction in area - may be of use in metal forming operations (e.g. - stretch forming). This is convenient for mechanical testing - but not very meaningful for most deformation processing. 2. Toughness- Area beneath str






16. Second phase particles with n > glass.






17. This strength parameter is similar in magnitude to a tensile strength. Fracture occurs along the outermost sample edge - which is under a tensile load.






18. There is always some statistical distribution of flaws or defects.






19. Undergo extensive plastic deformation prior to failure.






20. Rho=F/A - tau=G/A . Depending on what angle the force is applied - and what angle the crystal is at - it takes different amounts of force to induce plastic deformation.






21. 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






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






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






24. A high index of refraction (n value) allows for multiple internal reactions.






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


26. ...occurs in bcc metals but not in fcc metals.






27. 1. Stress-strain behavior is not usually determined via tensile tests 2. Material fails before it yields 3. Bend/flexure tests are often used instead.






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






29. 1. Necking 2. Cavity formation 3. Cavity coalescence to form cracks 4. Crack propagation (growth) 5. Fracture






30. The ability of a material to be rapidly cooled and not fracture






31. Resistance to plastic deformation of cracking in compression - and better wear properties.






32. - The emission of light from a substance due to the absorption of energy. (Could be radiation - mechanical - or chemical energy. Could also be energetic particles.) - Traps and activator levels are produced by impurity additions to the material - Whe






33. Different orientation of cleavage planes in grains.






34. Process by which geometric patterns are transferred from a mask (reticle) to a surface of a chip to form the device.






35. For a metal - there is no ______ - only reflection






36. Superconductors expel magnetic fields - This is why a superconductor will float above a magnet.






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






38. Reflectiviy is between 0.90 and 0.95 - Metal surfaces appear shiny - Most of absorbed light is reflected at the same wavelength (NO REFRACTION) - Small fraction of light may be absorbed - Color of reflected light depends on wavelength distribution of






39. Loss of image transmission - You get no image - There is no light transmission - and therefore reflects - scatters - or absorbs ALL of it. Both mirrors and carbon black are opaque.






40. 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






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






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






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






44. Degree of opacity depends on size and number of particles - Opacity of metals is the result of conduction electrons absorbing photons in the visible range.






45. Occur due to: restrained thermal expansion/contraction -temperature gradients that lead to differential dimensional changes sigma = Thermal Stress






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






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






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






49. Because of ionic & covalent-type bonding.






50. Flaws and Defects - They concentrate stress locally to levels high enough to rupture bonds.