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. 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






2. Impurities added to the semiconductor that contribute to excess electrons or holes. Doping = intentional impurities.






3. 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






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






5. A parallel-plate capacitor involves an insulator - or dielectric - between two metal electrodes. The charge density buildup at the capacitor surface is related to the dielectric constant of the material.






6. Second phase particles with n > glass.






7. 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.






8. Specific heat = energy input/(mass*temperature change)






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






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






11. 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






12. Allows you to calculate what happened G=F' x cos(lambda) - F=F' x cos(phi)






13. 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.






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






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






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






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






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






19. 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






20. 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






21. - 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






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






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






24. 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.






25. Stress concentration at a crack tips






26. Allows flow of electrons in one direction only (useful to convert alternating current to direct current) - Result: no net current flow






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






28. Materials change size when temperature is changed






29. 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






30. 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.






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






32. Width of smallest feature obtainable on Si surface






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






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






35. Occurs at a single pore or other solid by refraction n = 1 for pore (air) n > 1 for the solid - n ~ 1.5 for glass - Scattering effect is maximized by pore/particle size within 400-700 nm range - Reason for Opacity in ceramics - glasses and polymers.






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






37. Is analogous to toughness.






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






39. 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.






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






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






42. High toughness; material resists crack propagation.






43. Occur when lots of dislocations move.






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






45. These materials are relatively unaffected by magnetic fields.






46. Defines the ability of a material to resist fracture even when a flaw exists - Directly depends on size of flaw and material properties - K(ic) is a materials constant






47. 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.






48. Process by which metal atoms diffuse because of a potential.






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






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