A complete lunar phase cycle from one New Moon to the next takes about 29.5 days. Roughly how many days…

A complete lunar phase cycle from one New Moon to the next takes about 29.5 days. Roughly how many days elapse from the First Quarter phase to the Third Quarter phase?
  1. 7 days
  2. 15 days
  3. 22 days
  4. 29.5 days

Solution

The transition from First Quarter (one-half cycle point) to Third Quarter (three-quarters point) represents half of a full lunar cycle, which is about $29.5 / 2 \approx 14.75$ or roughly 15 days.

Asked in: Homi Bhabha Practice

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