Question

Important point about sound chapter class 9th????

Answer 1

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•sound is produced due to vibration of different object.

•sound Travels as or longitudinal wave through a material medium.

•sound Travels as successive compressions and refraction in the medium.

•in sound propagation , it is the energy of the sound that Travels and not the particle of the medium.

•sound cannot travel in vacuum.

•the change in density from one maximum value to minimum value and again to the maximum value make one complete oscillation.

•the distance between two consecutive compression or two consecutive Ray diffraction is called the wavelength .

•the time taken by the wave for one complete oscillation of the density of pressure of the medium called period.

•the number of complete oscillation per unit time is called frequency.

•the speed V frequency and wavelength of sound are related by equation.

•the speed of sound primarily on the nature and the temperature of the transmitting medium.

•the law of reflection of sound states that the direction in which the sound is incidents and reflected make equal angles with the normal to the reflecting surface at the point of incidence and the Three lie in the same plane.

•for hitting a distinct sound the time interval between the original sound and the reflected one must be at least 0.1 nd

•the precipitation of sound in an Auditorium is the result of repeated reflection of sound is called reverberation.

•sound properties such a page loudness and quality are determined by the corresponding wave properties
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Answer 2

☞HEYA MATE☜

★ SOUND

→ $<i>$ PRODUCED DUE TO VIBRATION OF OBJECTS ..

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⚫ PERIODIC MOTION : IT IS A MOTION WHICH REPEATS ITSELF IN EQUAL DISTANCE AND EQUAL INTERVAL OF TIME ..

⚫ OSCILLATORY : IF A BODY MOVES TO AND FRO MOTION REPEATEDLY ABOUT A MEAN POSITION ITS MOTION IS SAID TO BE OSCILLATORY MOTION ...

⚫ TIME PERIOD : IT IS THE TIME TAKEN TO COMPLETE ONE OSCILLATION ..

⚫ FREQUENCY : THE NUMBER OF OSCILLATION COMPLETED BY OSCILLATING BODY PER SECOND IS CALLED FREQUENCY ..

⚫ TRANSVERSE WAVES : THESE ARE WAYS IN WHICH THE PARTICLES OF THE MEDIUM VIBRATE IN A DIRECTION PERPENDICULAR TO THE DIRECTION OF WAVE MOTION ..

⚫ LONGITUDINAL WAVES : THESE ARE THE WAVES IN WHICH THE PARTICLES OF THE MEDIUM VIBRATE ALONG THE DIRECTION OF THE WAVE PROPAGATION ...

⚫ AMPLITUDE : IT IS THE MAXIMUM DISPLACEMENT SUFFERED BY THE PARTICLES OF THE MEDIUM FROM THEIR MEAN POSITION DURING THE WAVE PROPAGATION ..

⚫ WAVELENGTH : IT IS THE DISTANCE BETWEEN TWO COMPRESSION AND RAREFACTION ..

⚫ WAVE VELOCITY : WHAT IS THE DISTANCE TRAVELLED BY THE WAVE IN ONE SECOND ..

⚫ WAVE NUMBER : THE NUMBER OF WAVES CONTAINED IN THE UNIT LENGTH OF THE MEDIUM IS CALLED WAVE NUMBER ..

⚫ AUDIBLE RANGE OF FREQUENCY : HUMAN EAR IS SENSITIVE TO FREQUENCIES BETWEEN 2O HERTZ TO 20000 HERTZ ..

⚫ INFRASONIC WAVES : SOUND WAVES WITH FREQUENCY LESS THAN 20 HERTZ ..

⚫ ULTRASONIC WAVES : SOUND WAVES WITH FREQUENCY GREATER THAN 20000 HERTZ ...

☃️HOPE THIS HELPS UH ☃️