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






2. Undergo extensive plastic deformation prior to failure.






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






4. High toughness; material resists crack propagation.






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






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






7. 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






8. 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.






9. Because of ionic & covalent-type bonding.






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






11. ...occurs in bcc metals but not in fcc metals.






12. 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.






13. 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






14. 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.






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






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






17. 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






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






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






20. 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."






21. 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.






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






23. Sigma=ln(li/lo)






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






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

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






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






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






29. Width of smallest feature obtainable on Si surface






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






31. - 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






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






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






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






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






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






37. 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






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






39. 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






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






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






42. Light Amplification by Stimulated Emission of Radiation






43. 1. Insulators: Higher energy states NOT ACCESSIBLE due to gap 2. Semiconductors: Higher energy states separated by a smaller gap.






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






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






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






47. 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






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






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






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