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






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






4. Ohms Law: voltage drop = current * resistance






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






6. A three terminal device that acts like a simple "on-off" switch. (the basis of Integrated Circuits (IC) technology - used in computers - cell phones - automotive control - etc) - If voltage (potential) applied to the "gate" - current flows between th






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






8. 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






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






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






11. Width of smallest feature obtainable on Si surface






12. The magnetic hysteresis phenomenon: Stage 1: Initial (unmagnetized state) Stage 2: Apply H - align domains Stage 3: Remove H - alignment remains => Permanent magnet Stage 4: Coercivity - Hc negative H needed to demagnitize Stage 5: Apply -H - align d






13. 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






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






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






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






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






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






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






20. The ability of a material to absorb heat - Quantitatively: The energy required to produce a unit rise in temperature for one mole of a material.






21. 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






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






23. 1. Impose a compressive surface stress (to suppress surface cracks from growing) - Method 1: shot peening - Method 2: carburizing 2.Remove stress concentrators.






24. 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.






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






26. Different orientation of cleavage planes in grains.






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






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






29. Typical loading conditions are _____ enough to break all inter-atomic bonds






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






31. Cp: Heat capacity at constant pressure Cv: Heat capacity at constant volume.






32. 1. Hard disk drives (granular/perpendicular media) 2. Recording tape (particulate media)






33. Liquid polymer at room T - sandwiched between two sheets of glass - coated with transparent - electrically conductive film. - Character forming letters/ numbers etched on the face - Voltage applied disrupts the orientation of the rod- shaped molecule






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






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






36. Growing interconnections to connect devices -Low electrical resistance - good adhesion to dielectric insulators.






37. Undergo little or no plastic deformation.






38. (sigma)=F/Ai (rho)=(rho)'(1+(epsilon))






39. 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.






40. 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.






41. These materials are relatively unaffected by magnetic fields.






42. Diffuse image






43. 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






44. - A magnetic field is induced in the material B= Magnetic Induction (tesla) inside the material mu= permeability of a solid






45. 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






46. 1. Fluorescent Lamp - tungstate or silicate coating on inside of tube emits white light due to UV light generated inside the tube. 2. TV screen - emits light as electron beam is scanned back and forth.






47. Because of ionic & covalent-type bonding.






48. Sigma=ln(li/lo)






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






50. Stress concentration at a crack tips