Question

A ship sends a 1200 Hz sound wave down into the water, and detect the echo 3 seconds later. What would happen if that ship sent out a 600 Hz sound wave instead?

a) The sound would travel the same speed, so it would take half as much time to return
b) The sound would travel half as fas, so it would take twice as much time to return
c) The sound would travel twice as fast, so it would take twice as much time to return
d) The sound wave would travel the same speed, so it would take the same amount of time to return
e) The sound would travel twice as fast, so it would take half as much time to return

Answer 1

Step-by-step explanation:

Given that,

Ship send 1200Hz down in to the water.

Echo is heard after 3secs

f = 1200Hz

t = 3seconds

Using wave equation

V = fλ

In echo, two distance is travelled before echo can be heard, then we have

V = 2λ × f

Making d subject of the formula

λ = V / ( 2 × f)

So,

As frequency is reduced by half, the wavelength is double.

Notice

That the sound will travel the same distance but only the speed and the frequency will change.

So, the sound would travel twice as fast, so it would take half as much time to return