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. 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






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






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






4. High toughness; material resists crack propagation.






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






6. Cracks propagate along grain boundaries.






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






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






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






10. A high index of refraction (n value) allows for multiple internal reactions.






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






12. These materials are relatively unaffected by magnetic fields.






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






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






15. Second phase particles with n > glass.






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






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






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






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






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. Transmitted light distorts electron clouds - The velocity of light in a material is lower than in a vacuum - Adding large ions to glass decreases the speed of light in the glass - Light can be "bent" (or refracted) as it passes through a transparent






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






23. Is analogous to toughness.






24. 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.






25. Undergo extensive plastic deformation prior to failure.






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






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






28. 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.






29. 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.






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






31. - 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






32. 1. Electron motions 2. The spins on electrons - Net atomic magnetic moment: sum of moments from all electrons.






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






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






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






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

Warning: Invalid argument supplied for foreach() in /var/www/html/basicversity.com/show_quiz.php on line 183


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






38. 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.






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






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






42. Process by which metal atoms diffuse because of a potential.






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






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






45. 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)






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






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






48. Stress concentration at a crack tips






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






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

Warning: Invalid argument supplied for foreach() in /var/www/html/basicversity.com/show_quiz.php on line 183