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. Ohms Law: voltage drop = current * resistance






2. 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.






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






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






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






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






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






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






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






10. Allows flow of electrons in one direction only (useful to convert alternating current to direct current) - Result: no net current flow






11. 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)






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






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






14. 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.






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






16. Cracks propagate along grain boundaries.






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






18. Diffuse image






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






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






21. 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.






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






23. Is analogous to toughness.






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






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






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






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






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






29. Growing interconnections to connect devices -Low electrical resistance - good adhesion to dielectric insulators.






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






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






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






34. Undergo little or no plastic deformation.






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






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






37. 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.






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






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






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






41. 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.






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






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






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






45. - 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






46. 1. Tensile (opening) 2. Sliding 3. Tearing






47. 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






48. 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






49. Growth of an oxide layer by the reaction of oxygen with the substrate - Provides dopant masking and device isolation - IC technology uses 1. Thermal grown oxidation (dry) 2. Wet Oxidation 3. Selective Oxidation






50. 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