- 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

### Wavelength-

**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

**Amplitude**

- 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

### Time Period

**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

**Frequency**

**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

**Example**

**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 .

**Solution**

The Relationship between frequency wavelength and velocity is given by

**v= f ×****λ**

v= velocity of the wave

f=frequency

λ= Wavelength

**Velocity of the wave = Frequency ****× ****Wavelength**

So 343.4 = f × 1.7 × 10 ^{-2} m

**f = 2.02 × 10**^{4} Hz.

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