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Energy and Joule heating 
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#1
Mar1811, 01:14 PM

P: 7

1. The problem statement, all variables and given/known data
A solar panel (an assemblage of solar cells) measures 58 cm x 53 cm. When facing the sun, this panel generates 2.7A at 14V. Sunlight delivers an energy of 1.0 x 10^3 W/m^2 to an area facing it. What is the efficiency of this panel, that is, what fraction of the energy in sunlight is converted into electric energy? 2. Relevant equations Am I doing this problem correctly 3. The attempt at a solution The power delivered by the panel is P(delivered)= I x V= 2.7A x 14V= 37.8 W For the power delivered by sunlight I multiplied 1.0 x 10^3 W/m^2 by the area of .58m x .53m: so the area equals .307m^2. 1.0 x 10^3 W/m^2 x .307m^2= 307.4 W delivered by the sun. So I needed to find the fraction of energy in sunlight that is converted into electric energy. I did that by dividing 37.8W/307.4. The fraction of energy converted is .123 or 12.3%. Or is the answer 307.4/37.8= 8.13? I'm not sure which is the right answer or if it I did it correctly please let me know. 


#2
Mar1811, 01:21 PM

Mentor
P: 41,443




#3
Mar1811, 01:23 PM

P: 7

Thank you.



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