1. An array of solar panels on a residential roof produces (at full sun) 7.2 kW of dc power, &voltage of 600V a 40-ft Cu wire connects the panel from the roof to the inverter in the basement. At To= 20 degrees C, the electrical resistivity of copper is po= 1.67E-6 (omega*cm), and at higher temperatures, the resistivity of copper is p=po[a(T-To) with a=.0039/degrees C.
a. at 20 degrees c, what is the minimum diameter of the Cu wire, such that no more than 1% of the produced power is "consumed" by the resistance of the wire?
b. By what percentage does the resistivity of the Cu wire increase if temperature is raised from 20 degrees to 40 degrees C on a summer day?
2. The solar cells are made of silicon, with a band gap of 1.1 eV. The solar spectrum has wavelengths ranging from approximately 200 nm to 10 um. Some of the light is is absorbed in the Si while the rest of the light is traveling through the solar cell without being absorbed. Which part of the spectrum is absorbed in the silicon? provide the range of wavelengths
3. Diamond is considered as a possible element to make semiconducting devices; despite that the band gap of diamond is rather high. Looking at the periodic table, which element would you add to diamond to make it p-doped? why?