Answer: relative motion between observer and the sound source.
Explanation: The Doppler effect states that when there is a relative motion between an observer and a sound source the frequency of sound perceived by the observer is different in frequency from the original from the source.
The mathematical back up for this claim is given below.
f' = (v+v') /(v-vs) × f
Where f' = observed frequency
v = speed of sound in air
v' = velocity of observer
vs = velocity of source
f = frequency of sound source.
From the formulae, it can be seen that a change in the value of the velocity of observer (v') and source (vs) produces different value of observed frequency (f').
Note, frequency of sound (f) is a constant.
Answer:
45.1/3× 3.1/2 + 50.1/2× 2.1/2
=136/3. 7/2.+ 101/2× 5/2
=952/6 + 505/2
=( 952+ 1515)/6
=411.16
Explanation:
Make sure to read and go with it
Answer: The correct answer is vacuum.
Explanation:
Sound wave is a longitudinal wave in which the particles vibrate parallel to the direction of the motion of the wave. Sound wave consists of compression and rarefaction.
It needs a medium to travel. It can travel in solid, liquid and gas. It cannot travel in vacuum.
Denser the medium, more will be the speed of the wave.
Solid is more denser in comparison to liquid.
The speed of the sound in the solid medium is more in comparison to the liquid. The speed of the sound in liquid is more than the speed in the gas.
Therefore, vacuum is least effective medium for traveling sound waves.
