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






2. High toughness; material resists crack propagation.






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






4. 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






5. These materials are relatively unaffected by magnetic fields.






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






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






8. 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)






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






10. Occur when lots of dislocations move.






11. Undergo extensive plastic deformation prior to failure.






12. Light Amplification by Stimulated Emission of Radiation






13. Width of smallest feature obtainable on Si surface






14. Materials change size when temperature is changed






15. Emitted light is in phase






16. A parallel-plate capacitor involves an insulator - or dielectric - between two metal electrodes. The charge density buildup at the capacitor surface is related to the dielectric constant of the material.






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






18. Different orientation of cleavage planes in grains.






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






20. Ohms Law: voltage drop = current * resistance






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






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






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






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






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






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






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






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






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






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






32. 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






33. Because of ionic & covalent-type bonding.






34. - 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






35. Plastic means permanent! When a small load is applied - bonds stretch & planes shear. Then when the load is no longer applied - the planes are still sheared.






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






37. 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.






38. 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






39. 1. Yield = ratio of functional chips to total # of chips - Most yield loss during wafer processing - b/c of complex 2. Reliability - No device has infinite lifetime. Statistical methods to predict expected lifetime - Failure mechanisms: Diffusion reg






40. Defines the ability of a material to resist fracture even when a flaw exists - Directly depends on size of flaw and material properties - K(ic) is a materials constant






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






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






43. 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


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






45. Cracks propagate along grain boundaries.






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






47. Stress concentration at a crack tips






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






49. 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.






50. - 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