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






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






3. Heat capacity.....- increases with temperature -for solids it reaches a limiting value of 3R






4. 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.






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






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






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






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






9. Liquid polymer at room T - sandwiched between two sheets of glass - coated with transparent - electrically conductive film. - Character forming letters/ numbers etched on the face - Voltage applied disrupts the orientation of the rod- shaped molecule






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






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






12. Undergo extensive plastic deformation prior to failure.






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






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






15. 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






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






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






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






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






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






21. Different orientation of cleavage planes in grains.






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






23. 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.






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






25. 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






26. Second phase particles with n > glass.






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






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






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






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






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






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






33. 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."






34. 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.






35. 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.






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






37. Because of ionic & covalent-type bonding.






38. 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.






39. A high index of refraction (n value) allows for multiple internal reactions.






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






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

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42. Materials change size when temperature is changed






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






44. 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






45. 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.






46. 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.






47. 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.






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






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






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