1. A light source consists of monochromatic light with energy of 600 nm with a spectral irradiance of 1 x 1017 photons/cm²/sec. What is the power density of this light source? Is the light source visible to the human eye?
  2. The following questions involve calculations using the standard AM1.5 solar spectrum, available as an Appendix in the PVCDROM.
    1. For the AM1.5 solar spectrum, calculate the maximum current if every photon is absorbed and collected.
    2. A silicon solar cell has a band gap of 1.12 eV. What is the maximum current if every photon above the band gap gets absorbed and converted to current?
    3. What fraction of the total power in the AM1.5 spectrum is above the band gap of the silicon solar cell? What fraction is lost?
  3. The following question uses the standard AM1.5 solar spectrum, available as an Appendix in the PVCDROM. Calculate a running total, the total power, and a running total of the fraction of the total power for each wavelength for an for (i) and AM1.5G spectrum and (ii) a 6000K black body spectrum. At which wavelengths does the bulk of the difference between black body and AM1.5G occur?
  4. Assuming that the sun has a black body spectrum with the temperature at 6000K, what is the power density reaching the atmosphere of the Earth?
  5. How much does the solar radiation vary due to the Earth’s orbit? The average distance between the earth and sun is 149,600,000 km (defined as one Astronomical Unit (AU)). The radius of the sun is 6.96 x 105 km. At aphelion, the earth is 152,600,000 km away from the "center" of its orbit.
  6. For a location at 23° at the equinox, what is the Air Mass at solar noon? At 3 pm?
  7. Calculate the elevation and azimuth angle at solar noon for on Jan 1, March 21st and August 1st for your hometown. You may use as a default Belle Fourche, SD (the approximate geographic center of the US, with latitude of 44° 58' N, 103 ° 46' W).
  8. On April 14th, in Newark DE, what time of day will the clocks say when it is solar noon? Calculate an estimate for the solar radiation intensity at solar noon. Use 39° 30' N and 75° 30' W for the latitude and longitude of Newark.
  9. Calculate the azimuth and elevation angle for 2pm in Newark DE on Feb. 10th.
  10. Calculate the power on a module tilted at 30° at solar noon, for a location of 42° S and 147° E on Feb. 2nd if the incident radiation is 800 W/m². Repeat the calculation for the winter solstice and the Spring Equinox.
  11. The average monthly solar radiation for a several cities is given in the PVCDROM. What accounts for the greater variation in solar radiation over the course of the year in Seattle, Washington than in Maracaibo, Venezuela? For these two cities, calculate the average monthly radiation on a surface inclined at tilt = latitude and compare the radiation over a year. You  may assume mid-month at solar noon. Extra credit (1 pt total) Provide any three facts each about the locations Seattle, Washington and Maracaibo Venezuela.
  12. For a location at 25° N, estimate the solar radiation at 1 pm solar time on a sunny day by calculating the Air Mass.
  13. Derive the equation for solar elevation in northern hemisphere at solar noon.
  14. Assuming that the moon has an albedo of about 50%, estimate the power density of light from the moon at full moon on earth?
  15. A PV module (correctly installed and designed) points north, but it is actually in the northern hemisphere. Under what conditions might this occur?
  16.  In PV system (correctly installed and designed), some modules have an azimuth of 45°, while other modules have an azimuth of 315°. Under what conditions might this occur?
  17. At latitude of 30°> N, an overhang on a widow facing due south is designed such that the window does not get direct sun from May 21st to August 21st. What is the width of the overhang expressed as a fraction of the widow length? Is it possible to exactly meet these specifications? You should only have to do the calculations at solar noon.

  18. Prove that at the Equinoxes, the length of the night and day is equal everywhere in the world.
  19. PV modules are often tilted to latitude +15°. Why is latitude +15° used instead of tilt = latitude?
  20. Diffuse radiation has a higher fraction of high energy radiation than direct radiation. Explain why this is so.
  21. Using the solar calculators on the PVCDROM, a location at the equator has the same length of day all year. Physically explain why this is so.
  22. Write either a spreadsheet program or computer program to calculate the power density in kW/m²day (or in sun hours/day) for each day of the each for (a) a horizontal surface; (b) a surface tilted at an arbitrary angle.