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






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






3. 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)






4. Diffuse image






5. Light Amplification by Stimulated Emission of Radiation






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






7. 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






8. heat flux = -(thermal conductivity)(temperature gradient) - Defines heat transfer by CONDUCTION

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






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






11. 1. Ability of the material to absorb energy prior to fracture 2. Short term dynamic stressing - Car collisions - Bullets - Athletic equipment 3. This is different than toughness; energy necessary to push a crack (flaw) through a material 4. Useful in






12. 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






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






14. 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






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






16. - 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






17. Second phase particles with n > glass.






18. 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."






19. 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.






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






21. Width of smallest feature obtainable on Si surface






22. 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)






23. 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






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






25. 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.






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






27. 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.






28. 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.






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






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






31. 1. Fluorescent Lamp - tungstate or silicate coating on inside of tube emits white light due to UV light generated inside the tube. 2. TV screen - emits light as electron beam is scanned back and forth.






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






33. Different orientation of cleavage planes in grains.






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






35. 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






36. 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.






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






38. Occur when lots of dislocations move.






39. 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.






40. 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






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






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






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






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






45. 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.






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






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






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






49. Another optical property - Depends on the wavelength of the visible spectrum.






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