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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. Ohms Law: voltage drop = current * resistance






2. Second phase particles with n > glass.






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






4. 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."






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

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6. 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.






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






8. 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






9. 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)






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






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






12. Diffuse image






13. Undergo little or no plastic deformation.






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






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






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






18. Occur when lots of dislocations move.






19. 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.






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






21. Cracks propagate along grain boundaries.






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






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






24. 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.






25. 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.






26. Sigma=ln(li/lo)






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






28. 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.






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






30. 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






31. 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






32. High toughness; material resists crack propagation.






33. 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






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






35. Undergo extensive plastic deformation prior to failure.






36. 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






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






38. Emitted light is in phase






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






40. 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.






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






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






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






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






45. 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






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






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






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






49. Increase temperature - no increase in interatomic separation - no thermal expansion






50. These are liquid crystal polymers- not your normal "crystal" -Rigid - rod shaped molecules are aligned even in liquid form.

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