Hi there! I had the same question on my test as well!
The correct answer is (A) Homogeneous mixture!
I hope I helped you, and I am 100% this is the right answer!
Answer:
It lies in in the <u>visible</u><u> </u><u>region</u><u>.</u>
Frequency: <u>is</u><u> </u><u>7</u><u>.</u><u>4</u><u>0</u><u>7</u><u> </u><u>×</u><u> </u><u>1</u><u>0</u><u>^</u><u>-</u><u>1</u><u>4</u><u> </u><u>Hz</u>

Explanation:
V is speed of light.
f is frequency
lambda is the wavelength
I can’t see the picture for some reason
The air molecules in the compressions of the second wave are denser, so the sound is louder.
<h3>What is a sound wave?</h3>
Sound waves are longitudinal waves that travel through a medium like air or water.
In a closed room, Noah and Nina are sitting 15 m apart.
As Noah says the same sentence twice, Nina does not hear the sound the first time but she does hear the sentence the second time.
This happens as the air molecules in the compressions of the second wave are denser. As a result, the sound is louder.
The correct option is ''The air molecules in the compressions of the second wave are denser, so the sound is louder''.
Learn more about the sound wave here:
brainly.com/question/1554319
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