WHAT IS SOUND ?

sound is a vibration that audible by

mechanical wave of pressure and

displacement, through a medium such as air

or water.

SOUND WAVES ARE DIVIDED INTO TWO PARTS:-

1. LONGITUDINAL WAVES.

2. TRANSVERSE WAVES.

SOUND TRAVELS IN THE FORM OF WAVES.

WAVE:- IT IS A VIBRATORY DISTURBANCE IN A

MEDIUM WHICH CARRIES ENERGY FROM ONE

POINT TO ANOTHER WITHOUT THERE BEING A

DIRECT CONTACT B/W TWO POINTS.

IT IS OF TWO TYPES:-

1. LONGITUDINAL WAVE.

2. TRANSVERSE WAVE.

LONGITUDINAL WAVES:-

A WAVE IN WHICH THE PARTICLES OF MEDIUM

VIBRATE BACK AND FORTH IN SAME DIRECTION

IN WITH THE WAVE IS MOVING.

IT IS OF TWO TYPES:-

1. COMPRESSION.

2. RAREFACTION.

1. Compression:- It is the part of

longitudinal wave, in this wave the

particle of medium are very close to

one another, then they normally are and

there is momentary reduction in volume

of medium.

2. RAREFACTION:- IT IS THE PART OF

LONGITUDINAL WAVES IN WHICH THE

PARTICLES OF MEDIUM ARE FARTHER APART

THEN THEY NORMALLY ARE AND THERE

MOMENTARY INCREASES IN THE VOLUME OF

MEDIUM.

TRANSVERSE WAVE:-

IN THIS THE PARTICLES OF MEDIUM MOVE UP AND DOWN ‘AT RIGHT ANGLE’ IS CALLED TRANSVERSE WAVE.

IT IS OF TWO TYPES.

1. CRUST .2. TROUGH.

IT IS HUMP OR ELLIVATION PART OF TRANSVERSE WAVE, WHICH IS ABOVE THE ZERO

DISTURBANCE.

It is hollow and depression part of

transverse wave, which is below the zero

disturbance.

1. Sound can travel through in solid,

liquid gas.

2. Sound travel 15 times faster in

steel then air.

3. Sound cannot travel through

vaccum.

1. It depends on nature of material

through which it travel.

2. it depends on temperature.

3. it depends on humidity of air.

THE BOUNCING BACK OF SOUND WHEN IT

STRIKE A HARD SURFACE IS CALLED

REFLECTION SOUND.Sound

reflected here

Reflected

sound waveIncident

sound wave

Clock

EarNormal

TWO LAWS OF REFLECTION OF SOUND.

1. THE INCIDENT SOUND WAVE, REFLECTED

SOUND WAVE AND THE NORMAL AT THE POINT

OF INCIDENCE LIES ON THE SAME PLAIN.

2. ANGLE OF REFLECTION OF SOUND IS ALWAYS

EQUAL TO INCIDENCE OF SOUND.

The repetition of sound caused

by reflection of sound waves is

called echo.

APPLICATION OF REFLECTION OF SOUND.

1. MEGAPHONE:- IT IS A LARGE CONE

SHAPED DEVICE FOR AMPLIFYING THE

VOICE OF A PERSON WHO SPEAKS INTO IT.

It is a medical instrument

used by doctor for listening

produced with in the human

body mainly heart and lungs.

THREE PARTS:-

1. Chest piece 2. Ear piece

3. Rubber tube.

THE SOUND HAVE TOO HIGH FREQUENCY WHICH

CANNOT BE HEARD BY HUMAN BIENG SARE

CALLED ULTRA SOUND.

FREQUENCY= 20,000 HZ

RECIEVERTRANSMITTER

SHIP

Sea bed

SONAR:-

SONAR STAND FOR SOUND NAVIGATION AND

RANGING. SONAR IS A DEVICE THAT USES

ULTRA SONIC WAVES TO MEASURES THE

DISTANCE, DIRECTION AND SPEED OF UNDER

WATER OBJECT.

It is calculated by the method:-

2d = v * t

ADVANTAGES OF ULTRA SONIC WAVES:-

1). IT IS A HIGH FREQUENCY DUE TO WHICH

THEY CAN PENETRATE INTO SEA WATER TO A

LARGE EXTENT.

2). IT CANNOT BE CONFUSED WITH OTHER

SOUNDS OR NOISES.

HUMAN HEARINGsound wave

vibrates ear drum

amplified by bones

converted to nerve impulses in

cochlea