Question

the frequency of a sound wave is 4kHz and it's wavelength is 25 cm . find its speed ​

Answer 1

Given:-

→ Frequency of the sound wave = 4 kHz

→ Wavelength = 25 cm

To find:-

→ Speed of the wave.

Solution:-

Firstly, let's convert the units .

For frequency :-

⇒1 kHz = 1000 Hz

⇒4 kHz = 4(1000)

⇒4000 Hz

For wavelwngth :-

⇒1 cm = 0.01 m

⇒25 cm = 25(0.01)

⇒0.25 cm

Now, we know that :-

υ = νλ

Where :-

• υ is the speed of the wave.

• ν is frequency of the wave.

• λ is wavelength.

Susbtituting values, we get :-

⇒υ = 4000 × 0.25

⇒υ = 1000 m/s

Thus, speed of the sound wave is 1000m/s .

Some Extra Information:-

The speed of wave in a medium is the distance travelled by the wave per second.

⇒υ = Distance/Time

⇒υ = v/T

[∵ Distance travelled by a wave in T second is λ ]

∴ υ = νλ

Answer 2

Given -

Frequency of a sound wave is = 4kHz

Wavelength is = 25 cm

To find -

What is speed of the wave

Solution -

The Frequency

1 kHz = 1000 Hz

In the given question

4 kHz = 4(1000)

= 4000 Hz ✓

The wavelength -

1 cm = 0.001 m

In the given question

25 cm = 25(00.1)

= 0.25 cm ✓

We know that :

υ = ν λ

Need to know that -

υ = υ is the speed of wave

ν = ν is the frequency of wave

λ = λ is the wavelength

By doing substituting value , we will get :

υ = 4000 × 0.25 ( Multiplication )

υ = 1000 m/s ( m/s - metre per second )

Thus the speed of the sound wave is 1000 m/s