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. 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






2. 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.






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






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

Warning: Invalid argument supplied for foreach() in /var/www/html/basicversity.com/show_quiz.php on line 183


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






6. Failure under cyclic stress 1. It can cause part failure - even though (sigma)max < (sigma)c 2. Causes ~90% of mechanical engineering failures.






7. Transmitted light distorts electron clouds - The velocity of light in a material is lower than in a vacuum - Adding large ions to glass decreases the speed of light in the glass - Light can be "bent" (or refracted) as it passes through a transparent






8. Width of smallest feature obtainable on Si surface






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






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






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






12. Stress concentration at a crack tips






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






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






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






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






17. 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






18. 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.






19. Emitted light is in phase






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






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






22. 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






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






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






25. 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


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






27. 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.






28. 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.






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






30. 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






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






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






33. Is analogous to toughness.






34. 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






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






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






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






38. 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






39. Sigma=ln(li/lo)






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






41. Light Amplification by Stimulated Emission of Radiation






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






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






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






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






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






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






48. Because of ionic & covalent-type bonding.






49. As the applied field (H) increases the magnetic domains change shape and size by movement of domain boundaries.






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