Revision: Acoustics Science SSLC (English Medium) Class 10 Tamil Nadu Board of Secondary Education

The sound of frequency above 20,000 Hz is called ultrasonic.

The sound of frequency below 20 Hz is called infrasonic.

When a sound wave travels in a medium, the maximum displacement of the particle of the medium on either side of its mean position, is called the amplitude (a) of the wave.

The time taken by the particle of the medium to complete its one vibration, is called the time period (T) of the wave.

The distance travelled by a wave in one time period of vibration of the particle of the medium, is called the wavelength (λ).

The distance travelled by the wave in one second is called the wave velocity (V).

A pattern which moves through material medium by repeated vibration of the particles of the medium about their mean position without the actual movement of matter is called a wave.

The wavelength of a sound wave is the spatial distance over which the wave's shape repeats. Because sound is a longitudinal wave, it is specifically defined as the distance between two consecutive points in the same phase of vibration.

The process by which bats and dolphins detect the presence of an obstacle by hearing the echo of the sound produced by them is called sound ranging. 

The time period of a particle executing S.H.M. is the time taken to complete one cycle and is denoted by T.

The linear distance between the two consecutive particles of a vibrating medium in the same phase is called its wavelength. It is denoted by the Greek letter lambda (λ).

The number of vibrations made by the particle of the medium in one second, is called the frequency (j) of the wave.

Our ears are sensitive only to a limited range of frequencies from 20 Hz to 20,000 Hz, which is called the audible range of frequency.

The distance travelled by the wave in one time period of vibration of a particle of medium is called its wavelength. It's S.I. unit is metre (m).

The sound heard after reflection from a rigid obstacle (such as cliff, a hillside, a wall of a building, edge of a forest etc.), is called an echo.

The number of vibrations per second taken by a wave is called its frequency.

The number of vibrations made by a particle of the medium in one second is called the frequency of the waves. It is also defined as the number of waves passing through a point in one second. It's S.I. unit is hertz (Hz).

The maximum displacement of the particle of medium on either side of its mean position is called the amplitude of the wave. Its S.I. unit is a meter (m).

The return of a sound wave on striking a surface such as wall, metal sheet, plywood etc. back in the same medium is called the reflection of sound wave.

The distance travelled by a wave in one second is called its wave velocity. It's S.I. unit is metre per second (ms^-1).

The return of a sound wave on striking a surface such as wall, metal sheet, plywood etc. back in the same medium is called the reflection of sound wave.

The distance travelled by a wave in one second is called its wave velocity. It's S.I. unit is metre per second (ms^-1).

The distance travelled by the wave in one time period of vibration of a particle of medium is called its wavelength. It's S.I. unit is metre (m).

The sound heard after reflection from a rigid obstacle (such as cliff, a hillside, a wall of a building, edge of a forest etc.), is called an echo.

The number of vibrations per second taken by a wave is called its frequency.

The number of vibrations made by a particle of the medium in one second is called the frequency of the waves. It is also defined as the number of waves passing through a point in one second. It's S.I. unit is hertz (Hz).

The maximum displacement of the particle of medium on either side of its mean position is called the amplitude of the wave. Its S.I. unit is a meter (m).

The sound heard after reflection from a distant obstacle (such as a cliff, a hillside, wall of a building, edge of a forest, etc.) after the original sound has ceased, is called an echo.

The apparent change in frequency of sound heard by a listener due to relative motion between the source and the listener is called the Doppler effect.

The apparent change in the frequency of sound heard by a listener, due to relative motion between the source of sound and the listener is called Doppler effect in sound.

When the source and the observer are in relative motion with respect to each other and to the medium in which sound propagates, the frequency of the sound wave observed is different from the frequency of the source. This phenomenon is called Doppler Effect.

1. The angle of reflection is equal to the angle of incidence.
2. The incident ray, the reflected ray, and the normal lie in the same plane.
3. The incident ray and the reflected ray are on opposite sides of the normal.