# Sound wave

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#1
I would assume the wavelength is 5mm, and given the time is 0.2ms, the speed is 25m/s, and the frequency to therefore be 5kHz. Could someone please explain why the answer is "S only" and why the others are wrong?

Thank you.
0
1 month ago
#2
The amplitude of the wave is the maximum distance the loudspeaker cone moves backwards or forwards from its rest position, therefore 5/2 = 2.5mm
The time period(T) is given and frequency(f) is given by f=1/T so T= 5 kHz (so S is correct)

This f is entirely determined by the wave source( here, the loudspeaker ) and the wave speed is determined by properties of medium where the wave travels ( here, if it's air, factors like temperature, composition and humidity) and then the wavelength can be calculated from the equation v=fλ
v is not given( and we can't calculate it!) so we can't deduce the wavelength from the information given

hope this helps
0
1 month ago
#3
(Original post by eaglespirit)
The amplitude of the wave is the maximum distance the loudspeaker cone moves backwards or forwards from its rest position, therefore 5/2 = 2.5mm
The time period(T) is given and frequency(f) is given by f=1/T so T= 5 kHz (so S is correct)

This f is entirely determined by the wave source( here, the loudspeaker ) and the wave speed is determined by properties of medium where the wave travels ( here, if it's air, factors like temperature, composition and humidity) and then the wavelength can be calculated from the equation v=fλ
v is not given( and we can't calculate it!) so we can't deduce the wavelength from the information given

hope this helps
Could you not assume v=330m/s?
0
1 month ago
#4
(Original post by user342)
Could you not assume v=330m/s?
The question asks you to use only the information provided so disobeying that instruction would lose marks.
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