# Physics 10 Class Notes CHAPTER NO 11

Physics 10 Class Notes CHAPTER NO 11
Chapter NO. 11 SOUND

Major concept
- How sound is produced, the nature of sound.

- How sound is propagated.

- Characteristics of sound: loudness, intensity, pitch, quality, music, and noise.

- Intensity sound level, it’s unit and formula

- Echo, speed of sound.

- Noise pollution, the importance of acoustics.

- Audible frequency range.

- Ultrasound uses of ultrasound.

- The solution to problems.
Comprehensive Question
Q1: What is sound? How it is produced; transmitted and received? Ans. Sound:The stimulus due to a sounding body capable of producing a sensation of hearing is called sound.A sound is a form of energy that travels through a medium in the form of longitudinal (or) compressional waves. When sound fall on-ear membrane it produces a sensation of hearing.Generation of sound: Three things are necessary for the generation of sound.- i. Vibrating body.

- ii. Transmitting medium.

- iii. Hearing device.

- i. Loudness

- ii. Intensity

- iii. Pitch

- iv. Quality
I. Loudness: “The magnitude of auditory sensation produced by a sound is known as loudness.” “OR””The characteristic of sound by which we can distinguish between a Pc lod and f int sound is known as loudness”Loudn s directly depends upon the intensity of sound.ii. Intensity of sound:The energy transmitted per unit time by a sound wave through unit Varea placed perpendicular to the direction of propagation of waves is known of sound. “OR”
The power delivered by sound waves through the unit area is called intensity of sound
Mathematically:

I = -E —

At

Unit:W/m2is the SI unit of intensity of sound.Factors on which intensity and Loudness Depends: The intensity and loudness of a sound depending on the following factors.a) Amplitude of vibrating Body:The increase in the amplitude of the vibrating body causes an increase in intensity and loudness of sound. For example, A drum produces a loud sound when its membrane is struck strongly while the sound is faint when the membrane is struck gently.b) Frequency of vibrating Body:The increase in the frequency of the vibrating body also causes an increase in the loudness of sound. For example, the sound produce by a thin taut membrane of a drum is louder than the sound produces by the thick loose membrane of a drum.c) Surface Area of vibrating body:The increase in the surface area of the vibrating body causes an increase in the loudness of sound. For example, a dhool produces a louder sound as compared with dholak.d) Distance between the vibrating body and listener:The loudness of sound also depends upon the distance from the vibrating body. If the distance between the source and listener INCREASE THEN THE LOUDNESS OF SOUND DECREASE.

Physics 10 Class Notes CHAPTER NO 11 PDF

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