(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**

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

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

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