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Home » Class 9 » Sound » Characteristics of Waves

Characteristics of Waves

Last Updated on July 3, 2023 By Mrs Shilpi Nagpal

Question 1 What is the frequency of sound wave whose time period is 0.07sec?

Question 2 Define the term frequency?

Question 3 Define the term wavelength?

Question 4 Define the term wavelength?

Question 5 Define the term amplitude?

Question 6 What is the S.I. unit of frequency?

Question 7 The wave travels in a coiled spring at a rate of 4m/s.The distance between two consecutive compression is 20cm.Find wavelength and frequency of the wave? 

Question 8 Define the term tone?

Question 9 Define the term note?

Characteristics of Waves

characterstics of wave

1)Wavelength:The distance between two consecutive compression or rarefaction is called Wavelength.
or
The minimum distance in which a sound wave repeats itself is called wavelength.
It is represented by λ
Its unit is metre(m).

2)Frequency:The number of vibrations per second is called frequency.

or
Number of complete waves produced in one second.

Its unit is Hertz(Hz) or KiloHertz(KHz).

1KHz=1000Hz
When sound is propagated through a medium,the density of medium oscillates between maximum value and minimum value,makes one complete oscillation.

3)Time Period(T):The time period required to produce one complete wave.

                         1
Frequency=—————-
                   Time period
     1
f=——
      T
The time taken by two consecutive compression or rarefaction to cross a fixed point is called time period.
S.I. unit of time period is Seconds.

4)Amplitude:The magnitude of maximum disturbance in the medium on either side of mean value is called amplitude.
or
The maximum displacement of the particle of medium from their original undisturbed position,when wave passes through a medium is called amplitude.

The loudness or softness of sound is determined by its amplitude.

soft sound

loud sound

 The amplitude of sound wave depends upon the force with which an object is made to vibrate.

As sound wave moves away from source its amplitude as well as its loudness decreases.

The quality of sound is that characteristic which enables us to distinguish one sound from another having same pitch and loudness.

A sound of single frequency is called a tone.

A sound which is produced due to mixture of several frequencies is called note and is pleasant.

5)Velocity or Speed of wave
The distance travelled by a wave in one second is called velocity(v).
The S.I. unit of velocity of wave is metre per sec.
               Distance
Velocity=————-
                   Time

The amount of sound energy passing each second through unit area is called intensity of sound.

Loudness is a measure of response of the ear to the sound.

Filed Under: Class 9, Sound Tagged With: amplitude, characteristics of Waves, frequency, hertz, note, speed of wave, time period, tone, velocity, wavelength

About Mrs Shilpi Nagpal

Author of this website, Mrs. Shilpi Nagpal is MSc (Hons, Chemistry) and BSc (Hons, Chemistry) from Delhi University, B.Ed. (I. P. University) and has many years of experience in teaching. She has started this educational website with the mindset of spreading free education to everyone.

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