Answer:2.47
Explanation: did the math
Answer:
Amplitude is decreased by a factor of
if intensity is decreased by a factor of 3.
Explanation:
Intensity of a sound wave is directly proportional to the square of its amplitude.
Therefore, if intensity is
and amplitude is
, then
, where,
is constant of proportionality.
Now, if intensity of sound wave is decreased by a factor of 3. So,
New intensity is, 

Plug in
for
. This gives,

Therefore, amplitude is decreased by a factor of
.
Answer: B, increase the rate at which he turns the crank
Explanation: i got it right
Let the height where we are trapped is H
now to find the time to reach the key at the bottom is given as

now we have


now if the speed of sound is considered to be 340 m/s then time taken by the sound to reach at the top is given as

now the total time is given as

now by solving above equation we have
H = 48 m
now height of one floor is 3 m
so our position must be

Glass has a <u>grater </u>index of refraction than air. The glass's and air's indexes of refraction will be 1.5 and 1, respectively.
<h3>What is an index of refraction?</h3>
The refractive index of a substance is a dimensionless quantity that specifies how quickly light passes through it in optics.
The index of refraction of the glass and air will be 1.5 and 1 respectively.
Hence,glass has a <u>grater </u>index of refraction than air.
To learn more about the index of refraction, refer to the link;
brainly.com/question/23750645
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