Question

12. A sound wave has frequency 2 kHz and wavelength
40 cm in a given medium. Calculate the time taken by
it to travel 1.6 km in the given medium



13. A FM radio station broadcasts its programme at
93.5 MHz. If the speed of radio waves is
3 x 10 m s', find the wavelength of radio waves
emitted by the radio station.
nir at 300 K and​

Answer 1

Explanation:

12.)

We have :

Frequency of the wave, $\sf{\nu=2\:kHz=2000\:s^{-1}}$

Wavelength, $\sf{\lambda = 40 cm = 0.4 \:m}$

Distance travelled by the wave, $\sf{s = 1.6\:km =1600\:m }$

To find :

Time taken by the wave, $\sf{t=?}$

We know,

Speed of the wave, $\boxed{\sf{v=\lambda\times{\nu}}}$

$\implies{\sf{v=0.4\times{2000}}}$

$\implies{\boxed{\sf{v=800 \:ms^{-1}}}}$

Therefore,

time taken, $\boxed{\sf{t=\frac{s}{v}}}$

$\implies{\sf{t=\frac{1600}{800}}}$

$\implies{\underline{\boxed{\sf{t=2\:s}}}}$

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