The frequency of the wave is 6800 Hz
<u>Explanation:</u>
Given:
Wave number, n = 20
Speed of light, v = 340 m/s
Frequency, f = ?
we know:
wave number = 

Therefore, the frequency of the wave is 6800 Hz
Answer:
A) how your body uses oxygen
The phase is called 3rd quarter.
Hope this helps:)
Answer:
B. Developed out of efforts of man trying to explain our physical environment.
Explanation:
This is because physics, as we all know of, is considered to be <em>crucial to understanding the world around us</em>, making it the most basic and fundamental of science.