Question

the frequency of a source of a sound is 20khz find the wave length of the waves produced in air by the source if the speed of sound in air is 340m/s​

Answer 1

Answer:

Sound is produced due to vibration of objects.

Vibration is the rapid to and fro motion of an object.

WAVELENGTH : The distance two consecutive crest or two consecutive trough is called as wavelength.

It is denoted by a Greek letter : λ

S.I unit of wavelength is meter ( m ).

FREQUENCY : The number of oscillations per unit time is called frequency of the sound wave.

It is denoted by Greek letter ν ( nu ).

S.I Unit of the frequency is Hertz. ( Hz ).

→

Speed of sound in air = 340 m/s.

Frequency = 20kH z = 20 × 10³ Hz

Wavelength = ?

Therefore, Speed = Wavelength × Frequency

v = λν

Therefore, λ = v/ν = Speed / Frequency = 340 / 20 × 10³

= 0.017m.

Speed of sound in water = 1480 m/s

Frequency = 20 × 10³ Hz

Wavelength = ?

Therefore, Speed = wavelength × Frequency

Wavelength = Speed / Frequency

= 1480 / 20×10³

= 0.074 m.