15. What is the solar altitude on the 4th of July in Washington, D. C., at latitude 39"N? a. 22.7 b. 73.7 c. 23.5 d. 51° e. 90° 16. Through the whole year, the sun's declination migrates through a total of a. 23.5° b. 30° с. 470 d. 66.5° e. 133

answer 15 correct option is b. 73.7°

answer 16 correct option is с. 47°

Explanation:

we know that on 4th july Northen hemisphere have summer and Washington, D. C also in Northen hemisphere

and sun present at 23.5° latitude

so latitude of sun is calculate as given figure below

= 90° - (39° - 23.5°)

= 74.5°

so correct option is b. 73.7

this difference if because we take latitude 23.5° that is approx on 24 july

but july 4 latitude will be some low

and

we know during summer declination angle is + 23.5 in N. H.

and during winder declination angle is - 23.5 in N. H.

and at spring and autumn sun is at equator

the declination angle change is

declination angle change = 27.5 + 27.5 = 47°