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Unformatted text preview: University of California, Berkeley Fall 2010 EE 42/100 Prof. A. Niknejad Problem Set 1 Due Friday (5pm), September 10, 2010 Please complete this homework and turn it in to the drop box location in 240 Cory Hall (labeled EE 100). 1. Using the following information: Residential electric power costs $0.10 per kW hr Gasoline costs $3.20 per U.S. gallon, has a density of 720 kg / m 3 , and an energy density of 4 . 5 10 7 J / kg An AA battery costs $0.75, and supplies 100mA with terminal voltage of 1.5V for 20 hours before it is completely discharged Convert the cost of all three sources of energy into $ / J and compare. 2. Use the following information to solve this question. The average thermal energy of an electron, which determines its random or thermal velocity, is 3 2 kT , where k is Boltzmanns constant (1 . 38 10 23 J / K ) and T is the temperature in Kelvin The mass of an electron is 9 . 11 10 31 kg The density of free electrons in copper is 1 . 36 10 10 C / m 3 Cheetahs are the fastest land animals on Earth, running in short bursts at 28...
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