Is this question about sound waves incorrect?

[scrub2scrubs]

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I was taking a passage on M Prep- Qbank about sound waves and I think the answer they are giving is incorrect.

The question is:

The wave produced by a guitar is not considered a:

A) Standing Wave
B) Transverse Wave
C) Harmonic Wave
D) Longitudinal Wave

I said B, because sound waves are not transverse waves.

The answer they gave is D and this is their explanation: "Longitudinal waves have the same direction of travel and vibration, which is not usually possible in sound waves. Examples of this type of propagation are seismic waves. Standing, transverse, and harmonic waves are all the same type of wave propagation".

Isn't this wrong, or am I missing something?

 

[sazerac]

You are right, the answer is wrong. Sound waves are longitudinal pressure waves.

Maybe the author of the question was confusing guitars with guitar strings or something.

Good catch.

 

[Oso]

yeah sound waves are longitudinal. They can be longitudinal AND transverse in SOLIDS (weird, I know), but still doesn't make sense in this question. You're right, OP. Move on and don't let this psych you out. Good luck!

 

[scrub2scrubs]

Thanks guys!

 

[Schenker]

As others have said, this question is poorly worded, but it's still definitively answerable should you come across one like it on the MCAT. As you said the answer must be either B or D since only one of those can be true. Thus, the unspecified wave referred to in the question must be standing and harmonic, which are not properties of a sound wave produced by a guitar. Typically only wind instruments produce sound waves that are standing, something that can be deduced from knowledge of standing sound waves in open and closed pipes. This implies that the unspecified wave in the question must pertain to the only other wave relevant to a guitar, that which vibrates on a guitar string, which carries transverse waves.

I know it seems unfair to have to decode the question through the answer choices, but you may have to do so on the MCAT.

 

[brood910]

It is very poorly worded.
Waves in the air produced by the guitar string is longitudinal but the waves in the strings themselves are transverse.

 

[dudewheresmymd]

MCAT question of day has some poorly worded ones like this from time to time, skip and move on.