A singer moves a note up one octave. How has the sound changed?

The amplitude has decreased

The wavelength has increased

The speed has increased

The frequency has increased <-- im not sure, but i'm thinking that it's this one

yes, up means higher frequency

You're on the right track! When a singer moves a note up one octave, the correct choice is that the frequency has increased.

To understand why, let's break it down. When we talk about sound, it can be described in terms of various properties like amplitude, wavelength, speed, and frequency.

Amplitude refers to the intensity or loudness of sound waves. When the singer moves a note up one octave, the change in amplitude is not typically affected. So, we can eliminate this option.

Wavelength is the distance between two successive points in a sound wave, such as from crest to crest or trough to trough. Moving a note up one octave affects the pitch, not the physical distance between peaks (wavelength). Therefore, we can eliminate this option too.

Speed refers to how fast sound waves travel through a medium like air. However, changing the pitch or octave of a note does not affect the speed of sound. So, we can eliminate this choice as well.

Frequency, on the other hand, represents the number of complete cycles or vibrations that occur in a given time. When a singer moves a note up one octave, they essentially double the frequency of the original note. This means that the number of cycles or vibrations per second has increased, resulting in a higher pitch. Therefore, the correct answer is that the frequency has increased when the singer moves a note up one octave.

Remember, octave refers to a doubling or halving of frequency, which is why moving up one octave means the frequency has doubled.