EME 810
Solar Resource Assessment and Economics

3.4. Learning Activity: Laws of Light


Wolfram Alpha website is the Google of math and physics. If you want to do calculations on Wien's Law, you type "wien's law" and you will get a calculator for Wien's Law with all sorts of other information. The purpose of this activity is to practice some basic calculations of physical properties of sunlight.


  1. Use Wolfram Alpha to calculate the most probable wavelengths emitted by the surface of the Earth (T=300 K) and the Sun (T=5778 K) using one or more of the laws discussed on the previous page of this lesson. What is the meaning of the "most probable wavelength"? 
  2. Calculate the energy flux (power density) emitted by those Earth's and Sun's surfaces using Stefan-Boltzmann Law. 
  3. Apply the Inverse Square Law to determine the "extraterrestrial solar flux" at the Earth using the Sun's emitted flux found in Question 2. 
  4. What is the meaning of "extraterrestrial solar flux" and how is it further transformed within the Earth's atmosphere?

Submitting Your Work

Prepare a written report and upload your report to Canvas (Lesson 3 Learning Activity Dropbox) in PDF or docx format.

Grading Criteria

View the Rubric in Canvas by which this assignment will be graded.


See the Calendar tab in Canvas for specific due dates.