Question:
Why transverse wave does not travel through air or gases?
Answer:
In transverse waves, the particles of the medium vibrate perpendicular to the direction of propagation of the wave. The gas particles are loosely packed and compressible. The gas particles do not vibrate in perpendicular direction to the direction of propagation of sound.
Sound
Q 1.
How is sound propagated through a material medium ? What is wave motion ?
Q 2.
A hospital uses an ultrasonic scanner to locate tumors in a tissue. What is the wavelength of sound in a tissue is which the speed of sound is 1.7 km/s. The operating frequency of the scanner is 4.2 MHz. (1MHz = 10
6 Hz).
Q 3.
By how much does the speed of sound increase with rise of temperature ?
Q 4.
What is a wave number?
Q 5.
How are the wavelength and frequency of a sound wave related to its speed ?
Q 6.
What is audible range ?
Q 7.
Fill in the blanks :
Sound, compressional waves in springs are examples of _____________.
Q 8.
Fill in the blanks :
The product of wavelength of wave and its frequency gives _____________.
Q 9.
How are compressions and rarefactions produced near a source of sound ?
Q 10.
What is infrasonic? Give an example.
Q 11.
How does sound travel in gases and liquids as longitudinal or as transverse waves?
Q 12.
What are the factors speed of sound wave depends upon?
Q 13.
Obtain a relation between speed,frequency and wavelength of a wave.
Q 14.
What is Sound? Why it is important for us?
Q 15.
What is speed of sound in air?
Q 16.
Fill in the blanks :
v = ? × ?
Q 17.
Calculate the wavelength of a sound wave whose frequency is 220 Hz and speed is
440 m/s in a given medium.
Q 18.
What are ultrasonics?
Q 19.
Explain the working and application of a sonar.
Q 20.
What propagates along with the waves ?
Q 21.
Why are sound waves called mechanical waves ?
Q 23.
Fill in the blanks :
Ripples waves on water surface are example of ____________.
Q 24.
Three persons, A, B and C are made to hear a sound travelling through different mediums as given below:
| Persons | Medium |
| A | Iron Rod |
| B | Air |
| C | Water |
Who will hear the sound first? Why?
Q 25.
A sound wave travels at a speed of 339 ms
–1. If its wavelength is 1.5 cm, what is the frequency of the wave?
Q 26.
If 20 waves are produced per second, what is the frequency in hertz?
Q 27.
An observer standing at the sea coast observes 54 waves reaching the coast per minute.If the wavelength of a wave is 10 m,find the wave velocity.
Q 28.
An engine is approaching a hill at constant speed.When it is at a distance of 0.9 km,it blows a whisde,whose echo is heard by the driver after 5 s.If the speed of sound is 340 m/s,calculate the speed of the engine.
Q 29.
How can you show that sound waves are longitudinal waves ?
Q 30.
Fill in the blanks :
In a __________ wave the particles of the medium oscillate in a direction perpendicular to the direction in which the wave propagates.
Q 31.
Why sound waves are called mechanical waves?
Q 32.
A person is listening to a tone of 500 Hz sitting at a distance of 450 m from the source of the sound. What is the time interval between successive compressions from the source?
Q 33.
A person standing between two vertical cliffs and 680 m away from the nearest cliff,shouted.He heard the first echo after 4 s and the second echo 3 s later.Calculate (a) the speed of sound in air and (b) distance between the two cliffs.
Q 34.
sonar emits pulses on the surface of water which are detected after reflection from its bottom at a depth 1531 m.If the time interval between the emission and detection of the pulse is 2 s,find the speed of : sound in water.
Q 35.
Explain how sound is produced by your school bell ?
Q 36.
The sound of distant horses can be heard by applying the ear to the ground whereas it is inaudible if the ear is held a little distance above the ground.Explain.
Q 37.
What are transverse waves ?
Q 38.
Distinguish between music and noise.
Q 39.
Fill in the blanks :
Waves which require a material medium for propagation are called _____________ waves. Example of such waves is _________. Light waves are ___________, because they can travel in vacuum.
Q 40.
Fill in the blanks :
Sound travels as successive ____________ and _____________ in the medium.
Q 41.
Fill in the blanks :
In a _____________ wave the particles of the medium oscillate in the direction in which the wave travels.
Q 42.
Fill in the blanks :
Loudness of sound is measured in ___________.
Q 43.
What is a mechanical wave?
Q 44.
How does the sound produced by a vibrating object in a medium reach your ear?
Q 45.
Guess which sound has a higher pitch: guitar or car horn?
Q 46.
A boat anchor is rocked by waves whose consecutive crests are 100 m apart.If the wave speed of the moving crests is 20 m/s,calculate the frequency at which the boat rocks.
Q 47.
The sonic boom of an aircraft has a time period of 0 00005 s.Calculate the frequency of the sound produced.
Q 48.
A wave of wavelength 0-60 cm is produced in air and it travels at a speed of 300 m/s.Will it be audible ?
Q 49.
Calculate the wavelength of a sound wave whose frequency is 220 Hz and speed is 440 m/s in a given medium.
Q 50.
Distinguish between loudness and intensity of sound.
