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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. 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






2. Ohms Law: voltage drop = current * resistance






3. Diffuse image






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






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






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






7. 1. Stress-strain behavior is not usually determined via tensile tests 2. Material fails before it yields 3. Bend/flexure tests are often used instead.






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






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






10. Undergo extensive plastic deformation prior to failure.






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






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






13. 1. Tc= critical temperature- if T>Tc not superconducting 2. Jc= critical current density - if J>Jc not superconducting 3. Hc= critical magnetic field - if H > Hc not superconducting






14. Rho=F/A - tau=G/A . Depending on what angle the force is applied - and what angle the crystal is at - it takes different amounts of force to induce plastic deformation.






15. 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






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






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






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






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






20. Occur when lots of dislocations move.






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






22. 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






23. Is analogous to toughness.






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






25. Undergo little or no plastic deformation.






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






27. Digitalized data in the form of electrical signals are transferred to and recorded digitally on a magnetic medium (tape or disk) - This transference is accomplished by a recording system that consists of a read/write head - "write" or record data by






28. 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)






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






30. Emitted light is in phase






31. Stress concentration at a crack tips






32. 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.






33. 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.






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






35. - 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






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






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






38. (sigma)=F/Ai (rho)=(rho)'(1+(epsilon))






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






40. 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.






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






42. 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






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






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






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






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






47. 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.






48. 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.






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






50. Width of smallest feature obtainable on Si surface