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






2. 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






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






4. 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






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






6. Second phase particles with n > glass.






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

Warning: Invalid argument supplied for foreach() in /var/www/html/basicversity.com/show_quiz.php on line 183


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






9. 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.






10. Undergo extensive plastic deformation prior to failure.






11. These materials are relatively unaffected by magnetic fields.






12. Measures Hardness - No major sample damage - Each scales runs to 130 but only useful in range 20-100 - Minor load is 10 kg - Major load: 60 kg (diamond) - 100 kg (1/16 in. ball) - 150 kg (diamond)






13. Stress concentration at a crack tips






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






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






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






17. Dimples on fracture surface correspond to microcavities that initiate crack formation.






18. 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






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






20. 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.






21. Increase temperature - increase in interatomic separation - thermal expansion






22. - 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






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






24. 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






25. 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.






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






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






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






29. 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






30. - 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






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






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






33. High toughness; material resists crack propagation.






34. 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






35. 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.






36. 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






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






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






39. 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






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






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






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






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






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






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






47. Is analogous to toughness.






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






49. 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






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