Question

The first day of a month is the new moon day. On the fifteenth day of the same month, which of the following figures would represent the phase of the moon?
A.

B.

C.

D.

Answer 1

Hint: The moon revolves around the earth. This leads to the appearance of different phases of the moon from the Earth. This is because a portion of the moon is lit by the sun and is hence visible to us. There are 8 phases of the moon which take over 29.5 days to complete.

Complete answer:
We know that a moon reflects the sunlight falling on it and does not produce its own light. Due to tidal locking, the same side of the moon always faces the earth, but the angle in which the moon faces the changes.

The 8 phases of the moon are as shown as above:
1. New moon: the moon is not seen as it is unlit by the sun.
2. Waxing crescent moon: the size of the crescent increases.
3. first quarter moon: only one half of the moon is lit.
4. waxing gibbous moon: a little more than the half of the moon is lit.
5. full moon: here the moon is in the opposite direction of the moon, it takes about 15 days to reach this stage.
6. waning gibbous moon: the portion of moon which is lit decreases, and it is little less than the full moon.
7. last quarter moon: here the last half moon is lit.
8. waning crescent moon: the size of the crescent decreases further to give a new moon again, this is observed on the 29 day.

So, the correct answer is “Option A”.

Note:
Here, the phases are symmetric in nature. Hence the first four stages take 15 days and the next four stages take the next 15 days.