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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. 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






2. Because of ionic & covalent-type bonding.






3. 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






4. Heat capacity.....- increases with temperature -for solids it reaches a limiting value of 3R






5. - 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






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






7. Different orientation of cleavage planes in grains.






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






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






10. Undergo extensive plastic deformation prior to failure.






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

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






13. 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.






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






15. Width of smallest feature obtainable on Si surface






16. 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.






17. 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






18. Measures impact energy 1. Strike a notched sample with an anvil 2. Measure how far the anvil travels following impact 3. Distance traveled is related to energy required to break the sample 4. Very high rate of loading. Makes materials more "brittle."






19. Cracks propagate along grain boundaries.






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






21. Ohms Law: voltage drop = current * resistance






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






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






24. 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






25. These materials are relatively unaffected by magnetic fields.






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






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






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






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






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






32. 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.






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






34. Light Amplification by Stimulated Emission of Radiation






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






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






37. Is analogous to toughness.






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






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






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






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






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






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






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






45. Undergo little or no plastic deformation.






46. (sigma)=K(sigma)^n . K = strength coefficient - n = work hardening rate or strain hardening exponent. Large n value increases strength and hardness.






47. 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






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






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






50. 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