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. 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.






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






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






4. 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.






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






6. Emitted light is in phase






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






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






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






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






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






12. 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.






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






14. High toughness; material resists crack propagation.






15. These materials are relatively unaffected by magnetic fields.






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






17. Width of smallest feature obtainable on Si surface






18. Light Amplification by Stimulated Emission of Radiation






19. Cracks pass through grains - often along specific crystal planes.






20. Materials change size when temperature is changed






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






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






23. 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






24. The size of the material changes with a change in temperature - polymers have the largest values






25. 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)






26. Undergo extensive plastic deformation prior to failure.






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






28. Ohms Law: voltage drop = current * resistance






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






30. Undergo little or no plastic deformation.






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






32. Diffuse image






33. Occur when lots of dislocations move.






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






35. Different orientation of cleavage planes in grains.






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






37. 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.






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






39. Occurs at a single pore or other solid by refraction n = 1 for pore (air) n > 1 for the solid - n ~ 1.5 for glass - Scattering effect is maximized by pore/particle size within 400-700 nm range - Reason for Opacity in ceramics - glasses and polymers.






40. 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.






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






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






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






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






45. Dimples on fracture surface correspond to microcavities that initiate crack formation.






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






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






48. 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.






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






50. Small Coercivities - Used for electric motors - Example: commercial iron 99.95 Fe