There's a crest and a trough in each complete wave. So the question is describing 10 complete waves.
After that, the question becomes somewhat murky. It goes on to say "its time period is 0.2 seconds".
-- The "time period" of a wave is usually defined as the time for <u><em>one</em></u> complete wave. If that's what the phrase means, then ...
Frequency = ( 1/0.2sec )
<em>Frequency = 5 Hz.</em>
<em>= = = = = = = = = =</em>
<u>BUT</u> ... Is the question awkwardly trying to tell us that the <u><em>10 waves</em></u> take 0.2 seconds ? If that's what it's saying, then ...
Frequency = (10) / (0.2 sec)
<em>Frequency = 50 Hz .</em>
90.9 is the velocity of an airplane
Minerals of a single element are called Native elements. These include gold, silver, copper, etc. They can be divided into three groups such as metals, semi-metals, and nonmetals. Hope this helped.
I think it’s D, mostly just because all the other ones seem like they couldn’t be the answer.
