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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. Second phase particles with n > glass.






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






3. Different orientation of cleavage planes in grains.






4. Emitted light is in phase






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






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






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






8. Created by current through a coil N= total number of turns L= length of turns (m) I= current (ampere) H= applied magnetic field (ampere-turns/m) Bo= magnetic flux density in a vacuum (tesla)






9. 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.






10. 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.






11. 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






12. Measures Hardness 1. psia = 500 x HB 2. MPa = 3.45 x HB






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






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






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






16. Cracks propagate along grain boundaries.






17. 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






18. Width of smallest feature obtainable on Si surface






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






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






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






22. 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






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






24. Materials change size when temperature is changed






25. - 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






26. 1. Ability of the material to absorb energy prior to fracture 2. Short term dynamic stressing - Car collisions - Bullets - Athletic equipment 3. This is different than toughness; energy necessary to push a crack (flaw) through a material 4. Useful in






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






28. 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






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






30. Occur when lots of dislocations move.






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






32. 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






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


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






35. Cracks pass through grains - often along specific crystal planes.






36. Undergo little or no plastic deformation.






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






38. Undergo extensive plastic deformation prior to failure.






39. - 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






40. Diffuse image






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






42. Light Amplification by Stimulated Emission of Radiation






43. 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.






44. 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






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






46. Is analogous to toughness.






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






48. Ohms Law: voltage drop = current * resistance






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






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