UNIT-2

3. transfer of heat by the movement of fluids
5. length of days and nights are approximately equal
6. instrument that measures the global and diffuse solar irradiance on a planar surface.
7. the ratio of heat energy extracted from a collector to the solar energy striking the cover.
12. is the the total frequency spectrum of electomagnetic radiation produced by the sun
13. the sum of beam and diffuse radiation intercepted at the surface of the earth per unit area
14. device used to collect solar energy
15. the angle between sunrays and perpendicular to the horizontal plane.

1. the angle that a collector surface forms with a horizontal
2. are lenses ,mirrors that concentrate the light on to a small area
4. is solar irradiance that passes through the atmosphere in essentiallly a straight line.
8. the amount of electrical energy incident on a surface per unit time per unit area
9. instrument used to measure the intensity of radiant energy
10. surface of sun emmitting radiation
11. an instrument that measure net radiation at the earths surface