PasbanScienceCollege Khuiratta
Short Answer Questions
CH≠2(Physics for class 10th )
Prepared by Mr Qaisar Aslam

Q≠1.What is sound and how it is produced?
Sound is a form of energy and it is produced by a vibrating body.

Q≠2. In laboratory which device is usually used to produce sound?
Tuning fork is used. It is U-shaped having two metal prongs with a stem at the bottom.

Q≠3. What do you meant by sound waves?
Sound waves consist of compressional waves .They consist of compressions and rarefactions.

Q≠4. Show that medium is necessary for propagation of sound waves?
Experiment 13.1 from book.

Q≠5. Write down three parts of the ear?
(i) Outer ear (ii) Middle ear (iii) Inner ear

Q≠6. What is function of outer ear?
The external ear collects the sound waves and directs them to the ear drum.

Q≠7. Name the bones of the middle ear?
(i) Hammer (ii) Anvil (iii) Stirrup

Q≠8. What is ear drum? Describe function of ear drum?
Near outer earís center there is an opening canal which terminates at a diaphragm called the ear drum. When the sound waves reach the ear drum , they make it to vibrate. The ear drum separates outer ear from middle ear.

Q≠9. How do we hear sound?
We hear sound through ear which is a very delicate organ of our body.

Q≠10. Through what sound waves can travel?
Sound waves can travel through air , gases , liquid and solids.

Q≠11. What is the function of auditory nerves? OR
How message is send to the brain?
Message is send to the brain by auditory nerves.
Q≠12. Describe the function of middle ear?
The middle ear is a small cavity . The middle ear contains the small opening called oval windows .From the ear drum to oval window there are three bones anvil , hammer , stirrup . These bones start vibrating with sound and convey it to inner ear.

Q≠13. What are the characteristics of musical sound?
Musical sound has following characteristics
(i) Loudness (ii) Intensity of sound (iii) Pitch (iv) Quality

Q≠14. Does sound travel in vacuum , if your answer is no than show it by an experiment?
Experiment 13.1 from book.
Q≠15. Define loudness of sound?
It is such characteristic of sound by which a loud and faint sound can be distinguished.

Q≠16. On which factors loudness of sound depends?
It depends on amplitude and area of vibrating body and distance from vibrating body. It also depend on the physical condition of the ear.

Q≠17. Why sound produced by a sitar is loud if wires are plucked violently?
Because amplitude of the vibrating wires is increased so its sound is loud.





Q≠18. Why sound produced by a drum is loud, if we beat a drum forcefully?
Because its membrane vibrates with a large amplitude and a loud sound is produced.

Q≠19. Why sound produced by a large drum is louder than small drum?
Because the vibrating area of large drum is larger than small drum.

Q≠20. What happened if we place a vibrating tuning fork on the table?
When we place a vibrating tuning fork on the table, its sound becomes louder because the tableís top also vibrate along with tuning fork and total vibrating area increases.

Q≠21. Show that speed of sound in solid is greater than air?
Experiment 13.3 from book.
Q≠22. Name the characteristic of sound which does not depend upon condition of ear?
Intensity of sound which is a physical quantity does not depend upon the condition of ear.

Q≠23. Define intensity of sound along with unit? Sound energy flowing per second through a unit area held perpendicular to direction of sound waves is called intensity of sound .Its unit is Watt per square meter ().
Q≠24. Define Weber Fechner law?
According to this law , the loudness of sound is directly proportional to the logarithm of intensity.

Q≠25. What is meant by sound level (intensity level)?
The difference between loudness of unknown sound and loudness of faintest audible sound is called sound level.
is called sound level.
Q≠26. Write down the smaller unit of sound level or intensity level of sound?
The smaller unit is decibel (db) .
1 bel = 10 db
Q≠27. Calculate the intensity level of faintest audible sound?
Intensity level of faintest audible sound = _____(1)
For faintest audible sound = I=
And
By putting values in (1)
Intensity level of faintest audible sound = db
= 10 log 1 db
= 0 db (log1 = 0)
Q≠28. Calculate the intensity level of rustles of leaves?
For rustles of leaves =
Intensity level of rustles of leaves =
=
=
= ( log10 = 1)
= 10db
Q≠29. Calculate the intensity level of whispering?
For whispering =
Intensity level of whispering =









=
=
=
= db
= 20 db

Q≠30 . Define pitch of sound?
The characteristics of sound by which shrill and grave sound can be distinguished is called pitch of sound.
Q≠31. On which factor pitch of sound depends?
Pitch of sound depend on the frequency , higher the pitch , greater the frequency and lower the pitch lower will be the frequency.

Q≠32.Why voice of ladies and children is shrill land of high pitch than that of men?
Because the frequency of ladies and children is greater than that of men.
Q≠33. Show that pitch depend on the frequency of sound by an experiment?
Support a bicycle on stand and rotate its rear wheel .Touch a piece of cardboard with spokes of rotating wheel .We observed that cardboard is vibrating and producing a sound. If we increase the speed of rotation of wheel then we note that cardboard is vibrating more quickly and its frequency will start to increase . Thus sound produced will become shriller and of high pitch.

Q≠34. What happen if the amplitude of the sound is increased or decreased?
By increasing amplitude loudness of sound will increased or by decreasing amplitude loudness of sound will decreased.

Q≠35. What happen if area of vibrating body is increased or decreased?
By increasing area of vibrating body loudness of sound will increased or by decreasing area of vibrating body loudness of sound will decreased.

Q≠36. Define quality of sound ?
The characteristic of sound by which two sounds of same loudness and pitch are distinguished from each other is called the quality of sound.

Q≠37. How the sound produced by piano and tuning fork can be distinguished?
Both sounds have different quality so they can be distinguished.

Q≠38. Differentiate noise and music with examples?
Such sound which have pleasing effect on our ears is called music. For example sound of piano and sitar etc.
Such sound which have jarring effect on our ears is called noise. For example sounds of buses and motorcycles etc

Q≠39. Why ****** whistles are ****** for human but not for dog?
This whistle have frequency in between 20,000 to 25,000 Hz. This frequency is not audible for human so it is ****** for human but it is audible for dog and they can easily hear it.
Q≠40. Define resonance?
The phenomenon in which there is remarkable increase in amplitude and hence the loudness of sound when the frequency of air column becomes equal to that of the tuning fork is called resonance.

Q≠41.Prove that V=4fl?
As the distance between node and next antinode is equal to one quarter of wavelength ,hence
or
as we know
putting value of








Q≠42.What is meant by audible frequency range?
Audible frequency range lies between 20Hz to 20,000Hz.This range decreases with age .Young children can hear sounds of 20,000Hz but old people cannot hear sounds of above 15,000 Hz.

Q≠43.Why a vibrating simple pendulum does not produce any sound?
Simple pendulum does not produce any sound because its vibration are very slow.

Q≠44.Define ultrasonic?
Waves of frequency higher than 20,000Hz are called ultrasonic.

Q≠45. Name some major sources of noise pollution?
Autovehicles , aeroplanes helicopters heavy machinery , loudspeakers are the major sources of noise pollution.

Q≠46. Which sounds affect nervous system and cause hearing loss?
Sounds rated from 90db to 120db are annoying and affect nervous system and sounds more than 120db cause hearing loss and headache.

Q≠47. Why ultrasonic waves are used for scaling of teeth?
Because their vibration are so intense that they remove easily the dirt and plaque sticking to the teeth.

Q≠48. Write down two uses of ultrasonic waves in medical field?
The kidney stone can be crushed and removed out through urine with the help of ultrasonic waves.
To remove blood clots formed in the arteries , ultrasonic waves are used.

Q≠49. How depth of ocean can be measured by ultrasonic waves?
From the bottom of ship an ultrasonic pulse is sent down towards the ocean bed .Pulse after reflection reaches the ship where it is detected and the time taken by the pulse in traveling from the ship to ocean bed and back to the ship is measured. Using this time and speed of sound in water the depth of ocean can be measured .

Q≠50.How *****s appear in the interior of heavy machinery can be detected by ultrasonic?
When ultrasonic waves pass through these *****s , these waves are reflected from the surface of *****s .The reflected ultrasonic waves can give a clue of the existence of the *****s.

Q≠51.Why ultrasonic waves are usually utilized in medical and technical fields?
Because they carry more energy and wave length of these waves are very small .Generally waves ultrasonic waves of frequency higher than 20,000 Hz are utilized in medical and technical fields.

Q≠52. How can the resources of oil and gas beneath the earth are search?
The resources of oil and gas beneath the earth are searched by using ultrasonic waves.