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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. Because of ionic & covalent-type bonding.






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






3. 1. Diamagnetic (Xm ~ 10^-5) - small and negative magnetic susceptibilities 2. Paramagnetic (Xm ~ 10^-4) - small and positive magnetic susceptibilities 3. Ferromagnetic - large magnetic susceptibilities 4. Ferrimagnetic (Xm as large as 10^6) - large m






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






5. Typical loading conditions are _____ enough to break all inter-atomic bonds






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






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






8. 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






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






10. 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.






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






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






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






14. 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.






15. Emitted light is in phase






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






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

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






19. 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






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






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






22. 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






23. 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






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






25. 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.






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






27. - 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






28. 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.






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






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






31. Materials change size when temperature is changed






32. 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






33. 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






34. Sigma=ln(li/lo)






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






36. 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)






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






38. Occur when lots of dislocations move.






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






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






41. Cracks propagate along grain boundaries.






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

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43. 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.






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






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






46. High toughness; material resists crack propagation.






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






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






49. Width of smallest feature obtainable on Si surface






50. Undergo extensive plastic deformation prior to failure.