GATE-2018 (24) :Wyllie – Time average equation

CSIR_NET_DECEMBER_2018

123) At a latitude of 45⁰ in the northern hemisphere the solar Zenith angle at noon on the winter solstice is 

 

A) 45⁰ 

 B) 21.5⁰  

C) 68.5⁰  

D) 0⁰

(Thanks to Chandrasekhar, ANU)

Solution:

As we know Solar Zenith angle = Latitude – Declination

Declination during the winter solstice = -23.5⁰ ( since the sun is directly above the tropic of Capricorn)

Latitude = 45⁰ (given)

Therefore Solar Zenith angle = Latitude – Declination

                                             = 45⁰ – (-23.5⁰ )

                                              = 45⁰ + 23.5⁰

 

Solar Zenith angle = 68.5⁰

Note: During the Summer solstice we take declination angle as +ve

 

Reference: https://www.quora.com/At-a-latitude-of-45-degree-in-the-northern-hemisphere-the-solar-zenith-angle-at-noon-on-the-winter-solstice-is