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






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






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






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






5. 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






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






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






8. Undergo little or no plastic deformation.






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






10. - 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






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






12. Is analogous to toughness.






13. 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)






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






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






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






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






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






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






20. 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






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






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






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






24. Stress concentration at a crack tips






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






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






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






28. Different orientation of cleavage planes in grains.






29. 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.






30. 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






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






32. 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."






33. Second phase particles with n > glass.






34. 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.






35. Diffuse image






36. 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






37. Ohms Law: voltage drop = current * resistance






38. Superconductors expel magnetic fields - This is why a superconductor will float above a magnet.






39. 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)






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






41. Cracks propagate along grain boundaries.






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






43. 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






44. Materials change size when temperature is changed






45. Light Amplification by Stimulated Emission of Radiation






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






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






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






49. Width of smallest feature obtainable on Si surface






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