(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Given the following info:

Solar output(modulus of the Poynting vector): [itex]1.4kW/m^2[/itex]

Earth radius: 6370km

Average Earth orbit radius: [itex]1.49*10^11 m[/itex]

Find the total power output of the Sun, power received on the Earth, and the power received in Spain if its surface area is 5*10^2 km^2 and is at a latitude of 40 N.

2. Relevant equations

Poynting vector formula?

3. The attempt at a solution

I managed to get the right answer for the power received on the Earth, but I'm not sure how to proceed with the other 2 questions. Wouldn't the power received at a given latitude depend on the time of the year? I found this applet that calculates it for you and apparently at 40 N, the solar output never reaches 1.4kW at any time of the year:

http://pvcdrom.pveducation.org/SUNLIGHT/SHCALC.HTM

... so I'm guessing I'll have to resort to spherical trigonometry some way or another? I am given no other info and this is a course purely on electromagnetic optics.

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Solar irradiation on the Earth as a function of latitude.

**Physics Forums | Science Articles, Homework Help, Discussion**