
The 2 in front of
in
is <u>Coefficient.</u>
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The
after
in the same equation is <u>sub </u><u>script</u><u>.</u>
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There are two atoms of
in 
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Answer:
the answer is destructive interference
Https://www.youtube.com/watch?v=LXDG0nqYdR4
hope it helps ..............
Move anywhere and can be anywhere while it is in that phase