ss_9 - 2. The electrical conductivity of copper is...

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Unformatted text preview: 2. The electrical conductivity of copper is 5.8x10WQ—m)“. Determine the resistance of a copper wire which is 1 km long and 0.318 mm in diameter. '\_ \OODM L .. 4:: z 6;; ' E.¢ax%_b(¥\_ @Axams‘fi‘fii 4. A pure aluminum interconnect with a semicircular cross-section runs between two transistors on an integrated circuit. The intercminect is 10 microns long and has a radius of 200 nm. Across its length is a voltage of 5 V. The room-temperature conductivity of pure Al is 3.4 x107 (9 m)'l. (a) Determine the current density flowing through the interconnect. (b) The operating temperature of the device is 60 OC. Would you expect the current density flowing through the interconnect to be higher, lower, or the same as that at room temperature? Briefly justify your answer. (0) Suppose an Al - 5 wt% Cu alloy was used in place of pure aluminum. Would you expect the current density flowing through the interconnect to be higher, lower, or the same as that for a pure Al interconnect? Briefly justify your answer. V \J “E __\j__ =_ .yfi -: ""'-"' ® ems Per" 3 Wm M t" W Ewan \I 3—” 6 5 -.- \f‘l mfg “it” v) L‘ 13mm w h {,3- R “EV '33th M “\H (9 fl NWSRS WM T. s. as.» "i straws-’5‘ *8 T ‘W- “Ede © chmmx M W N \% Ramses KAN Iowa} ' 6. One important application of metal conductors is for wire in resistance-heated furnace elements. Consider a 1 mm diameter chromel (a Ni-Cr atloy) to produce a 1 kW furnace coil in a furnace operated at 110 V. (a) What length of wire would be required for this furnace design? The resistivity of chromel is LOSXIO‘6 Q-In at room temperature. (b) When in use as a heating element the temperature of the wire increases, and the resistivity of the chromel changes. How would you expect this change to affect the length of the wire you specify? Briefly justify your answer. (0) Suppose the wire is deformed prior to installation so it has a high concentration of defects such as dislocations and grain boundaries. How would this affect the calculation? Would the length need to be longer! shorter when using the high-defect wire. a \pcjzmifi: mm \GCMdKSAUZ: Tx go a SKAva - . V357; oath. © \W mm 3‘0 ax SWVW' \mcawvg Wt NAM®B New “em mafia m WWKG 7. The electricai conductivity of copper—zinc alloys (brasses) as a function of composition and degree of deformation is described in the adjacent figure. Rationalize the decrease in conductivity due to composition and deformation. 20 40 60 80 % deformation pure Cu 01- 10%Zn (Eu-15% Zn (In-20% Zn Cu-30% Zn 15. Suppose an insulating piece of pure SiOz (silicon dioxide) glass has a bandgap, Eg, of 6eV. (a) Quantitativer Show that this glass wouid be transparent to violet light with a wavelength of 300nm. (b) Suppose the SiOg contains a small concentration of impurities which introduce a donor level in the gap 1.0 eV below the bottom of the conduction band. Will the glass still be transparent to the Violet light? Justify your answer. __‘-__....‘-__.....m.__i._...wm.-_w_m O E ' 9M9 - 9A r. C?) \V' F B3961 LEW ® ‘WL Lima” wxw we shsd‘ckm EN Expirth $00715? £229.13 W W max LEURL no» E.st W 'so‘o N-x sea-mg NU: Why “to ‘M “has, WWW madam 16. How many atoms are contained in 1 cubic centimeter of silicon? If silicon is doped with 1018 atoms/cm3 of boron, how much boron has been added in terms of atomic percent? M M / '59 \‘6 —$ - 751M) 0 o w \L\OD \ 1“ 2w» J0) gm; 5 0007' 1’ W ...
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This note was uploaded on 10/03/2009 for the course E E344 taught by Professor Libera during the Spring '09 term at Stevens.

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ss_9 - 2. The electrical conductivity of copper is...

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