- Sound wave is longitudinal wave consisting of compression and rarefaction traveling through a medium
- To describe a sound wave we need to know five terms
- Time Period,Frequency,Wavelength,Amplitude,and Velocity
In the Above Image
- Sound Wave ABCDE and EFGHI .
- It starts from position A (normal density position) and compress along ABC and Rarefaction along CDE
- Again it returns to its normal position E
- Thus The ABCDE portion shows a complete Wave
- The Minimum Distance in which a sound wave repeats itself is called its wavelength
- It is denoted by the symbol lambda λ
- The Combined length of one compression and rare fraction is called its wavelength
- In the above figure the combined length of AC and CE means the length ACE is the wavelength
- The SI unit of wavelength is Meter
- When a wave passes through a medium ,the particles of the medium gets displaced temporarily from their original position
- In the Figure PB is the Amplitude
- The maximum displacement of the particle of the medium from their original undisturbed position is called amplitude
- The SI unit of Amplitude is Meter
- The Time required to produce one complete wave is called time period
- You can say the time taken to travel from Point A to point E is the time period
- The Unit of time period is Second
- The Number of complete cycles produced in one second is called Frequency
- The Unit of frequency is Hertz Hz.
Also F= 1/t
Where Frequency = 1/ Time Period
Velocity Of Wave(Speed of wave)
- The distance traveled by a wave in one second is called its velocity.
- Its unit is M/S
The Relationship between frequency wavelength and velocity
- If 25 sound waves are produced per second,what is the frequency in hertz.
Ans. As the name Says Frequency is equal to number of waves produced in a second .hence frequncy is equal to 25 hertz.
Now Another Problem
2.The Wavelength of a sound emitted by a source is 1.7 × 10 -2 m. calculate the Frequency of the sound if its velocity is 343.4 m/s .
The Relationship between frequency wavelength and velocity is given by
v= f ×λ
v= velocity of the wave
Velocity of the wave = Frequency × Wavelength
So 343.4 = f × 1.7 × 10 -2 m
f = 2.02 × 104 Hz.