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






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






3. 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






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






5. 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


6. Undergo extensive plastic deformation prior to failure.






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






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






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






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






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






12. Occur when lots of dislocations move.






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






15. 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






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






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






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






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






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






21. 1. General yielding occurs if flaw size a < a(critical) 2. Catastrophic fast fracture occurs if flaw size a > a(critical)






22. Different orientation of cleavage planes in grains.






23. 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."






24. Emitted light is in phase






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






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






27. Cracks propagate along grain boundaries.






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






29. Occurs at a single pore or other solid by refraction n = 1 for pore (air) n > 1 for the solid - n ~ 1.5 for glass - Scattering effect is maximized by pore/particle size within 400-700 nm range - Reason for Opacity in ceramics - glasses and polymers.






30. - 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






31. 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






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






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






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






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






36. Energy is stored as atomic vibrations - As temperature increases - the average energy of atomic vibrations increases.






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






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






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






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






41. Width of smallest feature obtainable on Si surface






42. These materials are relatively unaffected by magnetic fields.






43. 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






44. Materials change size when temperature is changed






45. 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.






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






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






48. Undergo little or no plastic deformation.






49. Diffuse image






50. 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.