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.
What is audible range ?
Q 3.
What is infrasonic? Give an example.
Q 4.
How are compressions and rarefactions produced near a source of sound ?
Q 5.
What are ultrasonics?
Q 6.
What are the factors speed of sound wave depends upon?
Q 7.
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 8.
How are the wavelength and frequency of a sound wave related to its speed ?
Q 9.
By how much does the speed of sound increase with rise of temperature ?
Q 10.
Fill in the blanks :
Sound, compressional waves in springs are examples of _____________.
Q 11.
How does sound travel in gases and liquids as longitudinal or as transverse waves?
Q 12.
What is speed of sound in air?
Q 13.
Calculate the wavelength of a sound wave whose frequency is 220 Hz and speed is
440 m/s in a given medium.
Q 14.
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 15.
A man standing at 51 m from a wall fires a gun.Calculate the time after which an echo is heard.The speed of sound is 340 m/s.
Q 16.
Obtain a relation between speed,frequency and wavelength of a wave.
Q 17.
What is a wave number?
Q 18.
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 19.
Explain how sound is produced by your school bell ?
Q 20.
Why do we use upholstered seats in theatres and halls ?
Q 21.
Fill in the blanks :
v = ? × ?
Q 22.
Give an application use of ultrasonics.
Q 23.
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 24.
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 25.
Why are sound waves called mechanical waves ?
Q 26.
What propagates along with the waves ?
Q 28.
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 29.
Try to imagine what you would feel, what sort of person you would be,had you been born totally deaf.
Q 30.
Fill in the blanks :
A ________ (pulse/wave) is a form of disturbance which travels through a medium as a result of repetitive oscillations of the particles of the medium.
Q 31.
Fill in the blanks :
Full form of SONAR is __________________________.
Q 32.
What is a mechanical wave?
Q 33.
How does the sound produced by a vibrating object in a medium reach your ear?
Q 34.
Why transverse wave does not travel through air or gases?
Q 35.
What are wavelength, frequency, time period and amplitude of a sound wave?
Q 36.
If 20 waves are produced per second, what is the frequency in hertz?
Q 37.
What type of wave is represented by density- distance graph?
Q 38.
How does the sound produced by a vibrating object in a medium reach your ear ?
Q 39.
What is the audible range of the average human ear ?
Q 40.
Explain the working and application of a sonar.
Q 41.
What is persistence of hearing ?
Q 42.
Discuss the structure of human ear from auditory aspect only.
Q 43.
On what factors does the speed of sound in a material depend ?
Q 44.
Fill in the blanks :
Number of oscillations completed by the oscillator in one second is known as ___________.
Q 45.
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 46.
What type of waves can travel in vacuum? Give example(s).
Q 47.
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 48.
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 49.
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 50.
Distinguish between loudness and intensity of sound.
