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






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






3. 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






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






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






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






7. 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






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






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






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






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






12. 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






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






14. High toughness; material resists crack propagation.






15. Occur when lots of dislocations move.






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






17. Undergo little or no plastic deformation.






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






19. 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.






20. Wet: isotropic - under cut Dry: ansiotropic - directional






21. Is analogous to toughness.






22. Cracks propagate along grain boundaries.






23. 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.






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






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






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






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






28. 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."






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






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






31. Because of ionic & covalent-type bonding.






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






33. 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






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






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






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






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






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






39. Width of smallest feature obtainable on Si surface






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






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






42. Undergo extensive plastic deformation prior to failure.






43. 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.






44. 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






45. These materials are relatively unaffected by magnetic fields.






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






47. Diffuse image






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






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






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