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. Undergo extensive plastic deformation prior to failure.






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






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






4. 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






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






6. Because of ionic & covalent-type bonding.






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






8. 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






9. 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.






10. 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






11. Diffuse image






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






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






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






15. 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.






16. Large coercivities - Used for permanent magnets - Add particles/voids to inhibit domain wall motion - Example: tungsten steel






17. - 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






18. Different orientation of cleavage planes in grains.






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






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

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






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






23. 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.






24. Undergo little or no plastic deformation.






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






26. 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.






27. 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






28. 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.






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






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






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






32. 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






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






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






35. 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.






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






37. Failure under cyclic stress 1. It can cause part failure - even though (sigma)max < (sigma)c 2. Causes ~90% of mechanical engineering failures.






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






39. Cracks propagate along grain boundaries.






40. Light Amplification by Stimulated Emission of Radiation






41. 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.






42. 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.






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






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






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






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






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






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






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






50. 1. Tensile (opening) 2. Sliding 3. Tearing