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3 years ago

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What is the frequency of sound waves whose wavelength is 0.25 m on a day when the air temperature is 25 degree Celsius? Group of

answer choices
1200 Hz
1384 Hz
1730 Hz
2400 Hz
3000 Hz

2 answers:

anzhelika [568]3 years ago

8 0

Answer:

Frequency, f = 1384 Hz

Explanation:

It is given that,

Wavelength of the sound wave, $\lambda=0.25\ m$

Air temperature, T = 25° C

The speed of sound at a particular temperature is calculated as :

$v=331.5+0.6\times T$

$v=331.5+0.6\times 25$

v = 346.5 m/s

Let f is the frequency of the sound wave. It can be calculated as :

$f=\dfrac{v}{\lambda}$

$f=\dfrac{346.5\ m/s}{0.25\ m}$

f = 1386 Hz

or

f = 1384 Hz

So, the frequency of sound waves is 1384 Hz. Hence, this is the required solution.

Dvinal [7]3 years ago

5 0

Answer:1384 Hz

Explanation:

Given

wavelength $(\lambda )$ =0.25 m

Temperature T $=25^{\circ}$

at $T=25^{\circ}$ velocity of sound is 346 m/s

and we know

$velocity=frequency\times \lambda$

$v=f\times \lambda$

$346=f\times 0.25$

f=1384 Hz

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anzhelika [568]

Missing data in the text of the exercise: The molar concentration of Zinc is 10 times the molar concentration of copper.

Solution:

1) First of all, let's calculate the standard electrode potential difference at standard temperature. This is given by:
$E^0=E_{cat}^0-E_{an}^0$
where $E_{cat}^0$ is the standard potential at the cathode, while $E_{an}^0$ is the standard potential at the anode. For a Daniel Cell, at the cathode we have copper: $E_{Cu}^0=+0.34 V$ , while at the anode we have zinc: $E_{Zn}^0=-0.76 V$ . Therefore, at standard temperature the electrode potential difference of the Daniel Cell is
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2) To calculate $E^0$ at any temperature T, we should use Nerst equation:
$E^0(T)=E^0- \frac{R T}{z F} \ln \frac{[Zn]}{[Cu]}$
where
$R=8.31 J/(K mol)$
$T=473.15 K$ is the temperature in our problem
$z=2$ is the number of electrons transferred in the cell's reaction
$F=9.65\cdot 10^4 C/mol$ is the Faraday's constant
$[Zn]$ and $[Cu]$ are the molar concentrations of zinc and in copper, and in our problem we have $[Zn]=10[Cu]$ .
Using all these data inside the equation, and using $E^0=+1.1 V$ , in the end we find:
$E^0(T)=E^0- \frac{R T}{z F} \ln \frac{[Zn]}{[Cu]}=+1.053 V$

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