Question

A sound wave has a frequency of 10 kHz and wavelength 3 mm. How much time will it take to travel 3 metre?
(Raj./NTSE Stage-1/2018)
(A) 0.1 sec
(B) 1 sec
(C) 10 sec
(D) 0.01 sec.​

Answer 1

Answer:

A

Explanation:

• v=n× λ
• v=x/t

given;

λ=0.003m

n=10000hz

x=3m

v=(0.003)(10000)

=30m/s ...............(1)

v=3/t.................(2)

from 1 and 2

we get t =0.1sec

Answer 2

The time taken by the sound wave to travel 3 meters is 0.1 seconds.

Explanation:

It is given that,

Frequency of the sound wave, $f=10\ kHz=10^4\ Hz$

Wavelength, $\lambda=3\ mm=0.003\ m$

If v is the speed of sound wave. It can be calculated as :

$v=f\times \lambda$

$v=10^4\times 0.003$

v = 30 m/s

Let t is the time taken by the sound wave to travel 3 meters. It is given by :

$v=\dfrac{d}{t}$

$t=\dfrac{d}{v}$

$t=\dfrac{3\ m}{30\ m/s}$

t = 0.1 seconds

So, the time taken by the sound wave to travel 3 meters is 0.1 seconds. Hence, this is the required solution.

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