10th Class Physics Chapter 11 Short Questions with Answers Solved

Question: 1

Define Sound is reflected Explnation.

Answer: 1

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Question: 2

What is intensity level?

Answer: 2

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Inrwnairy Level: The differencebetween the loudness of two sounds where one sound is faintest audible is known as intensity level.

Explanation: An aveage human ear can detect sound with intensity as low as 10-12 W/m2 and as high as 1 W/m2 this is an incredibly wide rangeof intensity. spanning a factor 10¹²from lowest to highest. It L is the loudness and 'I' is the sound intensity in W/mw ,then mathematically

L inversal log I

Question: 3

Define Quality Explanation and example

Answer: 3

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Quality: The property of sound by which two sounds of the same loudness and pitch are distinguish from each other

Explanation: With the helpof quality os sound, we can distingush between soundof one instrument from the sound of another instrument, although they have the same pitch and loudness.

Example: When a piano and a flute are made toproduce sound of same loudness andpitch, we can easily distinguish between the overall sound from piano and flute.

Question: 4

What is audible frequnecy range?

Answer: 4

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Audible Frequencey Range: There are both upper and lower limits to the sound frequencies that human can hear.A healty young person can typically hear freuencies in range from about 20 Hz to 20,000 Hz.The upper limit edecrease with age.

Physicists have established a three part classification of sound, based on the range of human hearing.

Question: 5

What is Infrasonic.

Answer: 5

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Infrasonic: Sound frequencies lower than 20 Hz are referred to as infrasonic.so, these sounds cannot be heared by human beings, The soundsproduced by whales, elephants and rhinoceroses are infrasonci.

Question: 6

What is noise ad explanation.

Answer: 6

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Question: 7

What is sound? How it is produced.

Answer: 7

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Sound: The sensation feld by our ears is called sound.

Explanation: Sound is the form of energy It travels through a medium in the form of longitudinal waves. When sound falls on the ear membrane it produces the sensation of hearing.

Production os Sound:

Some distrurbance and vibration isneededfor the productionof sound.

In tunning fork expriement, when the prongs of the tuning fork are struck on a hard rubber pad, the prong vibrates and sound is produced in the form of compression and rarefactions.Buzzing sound of bees and mosquitoes is produced due to rapid vibrations of their wings.Sound in sitar and guitar is produced by vibration of stretched string.

Question: 8

Define Term loudness.

Answer: 8

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Loudness: The greater the sound energy, the louder is the sund.The lodness depends upon the ampliteud of the osund waves.

Explanation: The loudness of the sound enable us to distinguish between a faint and the loud sound. Loudness depends upon the following factors.

i. The area of vibrating body:

Larger the are of vibration larger will be amplitude of sund produced.

ii- Distance from the sources of sound:

The loudness of a sound increases or decreases as the distance between the surce of sound and the listneer decreses or increases respectively.

3- Metarial through which sound in traveling:

amplitude of sound wave is differnet in different materials such as, water and air.

Example: A drum produces loud sound if its memberane is struck strongly. This is because the vibrating body starts to oscillate with larger amplitude and there fore the sound it produced also has a larer amplitude and as a result the sound is louder.

Question: 9

Define Audible sound

Answer: 9

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Soundfrequencies in 20 Hz to 20,000 Hz rangeare audible.

Question: 10

Define Pitch explanation and example

Answer: 10

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Pitch: The pitch of sound is the characteristic of sound by meansof which a shrill sound can be distinguish rom a gave sound.

Explanation: The pitch of a note depends on the frequeny of the sound wave reachign the ear. ahigh pitched note has a high frquency and a short wavelength. A low pitched note has a low frquency and long wavelngth.

Example: The sound produces by man, dogs, frogs etc.are of low pitch whereas the sound produced by women, birds, cats etc.are of high pitch. Pitch is like color inligh both depend on the frequency.

Question: 11

What is the speed of sound?

Answer: 11

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The speed of sound is the distance traveled per unit time by a sound wave as it propagates through a medium.

Explanation:

The speed of sound depends upon the material through which it is passes. Sound can be transmitted through any medium solid , liquid or gas. Sound travels most rapidly in certain solids less rapidly in many liquids, and quit slowly in most gases.

The speed of sound 'v' can be found by dividing distance 'S' by time 't' as.

Speed = distance /time

or V = S/t

Question: 12

Define Ultrasonic.

Answer: 12

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Sound frequencies higher than 20,000 Hz are known as ultrasonic,So, these sounds cannot be heared by human beings because these are outside the audible range of humnan.The sound produced by bats. These are very powerful waves and can be used in medical, scientific and industiral fields for various purposes.

Question: 13

Why is it so quiet after a snowfall?

Answer: 13

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Snow is porous and is a good sound absorber. When snow accumulates on the gound, it acts as a sound absorber damping sound waves like other sound absorbing materials.Snow wraps everything in a thick blanket, which acts as a sound barier.A very little sound energy is refleted when sound waves hit the snow surface. Due to its porous nature, sound waves center into its surface and make multiple reflectins, dut to which considerale amount of energy is absorbed Thus there is so quite after a snow fall.

Question: 14

Why does your voice sound fuller in the shower?

Answer: 14

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Question: 15

If a ringing bicycle bell is held tightly by hand, It shops producing sound. why?

Answer: 15

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When a body vibrates sound is produced due to vibration. Thus if a ringing biycles bell is held tightly by hand it stopes producing sound because its bivrations die out and as a result bell will produce no sound

Question: 16

Why is the intensity of an echo less than that of oriignal sound.

Answer: 16

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The intensity of an echo less than that of original sound because intensity decreasses with distance and the sond has traveled from the soufce to a reflecting surface and back.

When the sound strikes with wall it imparts some of its energy to the wall.Thus the reflected waves possess less energy and become less intense.There fore, the intensity of an echo is less intense than the original sound waves.

Question: 17

Why soudn produced by a simple pendulum is not heard?

Answer: 17

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The waves produces by a simple pendulum not heard because the frequency of these waves is less than 20 Hz and the memebrane of human ear can only detect those sound whose frequency is greater than 20 Hz and below than 20,000 Hz. The frequency of waves produced by a siple pendulum is less than 20 hz that is why we cannot hear such sounds of low frequencies.

Question: 18

When you watch a thunderstorm, you see the lightning first , andyou hear the thunder afterward.Why is the thunder dealyed?

Answer: 18

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he thunder light is seen elarlier than thunder sound is heard because light travels much faster than sound in air.

Speed of light in air eis 3 x 10⁸ m/s wheas the speed of sound in air is 343 m/s. Ths, because of this reason we see the light of thunder much earlier than we hear its sound.

Question: 19

In which medium air or water, an echo heard sooner.Why?

Answer: 19

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An echo is heard sooner in water as compared to air because the speed of sound depends on the elasiticity of the medium. The more elastic a medium the greater willbe the speed of sound and vice versa. So, water is more elasticthan air. The sond will travel faster in water that is why, We heard on echo sooner in water as compare to air.

Question: 20

If the speed of sound is dependent on frequency, would music from marching band be enjoyed?

Answer: 20

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Question: 21

If a person places his car on rails of rairoad for determinateionof coming triain. Why is this done, and how does it work?

Answer: 21

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Question: 22

Why sound cannot be heard on moon.?

Answer: 22

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Sound waves are longitudinal waves which needs a material medium for their propagation.Inmoon atmosphere there is no material medium tha tis why sound cannot be heard on moon.

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10th Class Chapter 11 Physics Short Questions

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