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. 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






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






3. 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






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






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






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






7. - 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






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






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






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






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






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






13. Ohms Law: voltage drop = current * resistance






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






15. Width of smallest feature obtainable on Si surface






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






17. 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






18. Not ALL the light is refracted - SOME is reflected. Materials with a high index of refraction also have high reflectance - High R is bad for lens applications - since this leads to undesirable light losses or interference.






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






20. 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.






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






22. 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.






23. 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.






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






25. 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


26. - 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






27. 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.






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






29. Occur when lots of dislocations move.






30. The ability of a material to transport heat - Atomic Perspective: Atomic vibrations and free electrons in hotter regions transport energy to cooler regions - Metals have the largest values






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






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






33. High toughness; material resists crack propagation.






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






35. Cracks propagate along grain boundaries.






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






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






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






39. 1. Ductility- % elongation - % reduction in area - may be of use in metal forming operations (e.g. - stretch forming). This is convenient for mechanical testing - but not very meaningful for most deformation processing. 2. Toughness- Area beneath str






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






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






42. Undergo extensive plastic deformation prior to failure.






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






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






45. Light Amplification by Stimulated Emission of Radiation






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






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






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






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






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