The question was: \"As a sound wave passes from water, where speed is 1.49 E 3 m

Question

The question was:

"As a sound wave passes from water, where speed is 1.49 E 3 m/s,into air, the wave's speed:"

The answer was:

"decreases and its frequency remains the same"

Now, I do understand the frequency concept. But, I don'tunderstand why the speed decreases. Using the concept ofrefraction of light waves, I assumed that since index of refractionof air is lower than index of refraction of water and thus thespeed of the wave increases when passing from air to water. Can someone please explain to me why the answer is"decreases"? Is it because the concept of refraction differswhen talking about sound waves as opposed to light/EM waves? Orwhen talking about one type of wave versus another type?

Thank you

Explanation / Answer

No , concept remains the same for EM waves and sound waves , Difference is the concept of rarer and denser for different waves. We know , refractive index =Speed of wave in air(or vacuum) /speed of wave in medium For light waves , refractive index of water is higher than that of refractive indexof air . But for sound waves , As given ,speed in water =1.43E3 m/s Also speed in air is around 330 m/s So refractive index is less than that of air , So water is a rarer medium as compared to air for sound waves ,butit is opposite for light waves .

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.