Question:
Which wave characteristics determine the
(a) Loudness (b) pitch of sound?
Draw two different waveforms and mark these characteristics on it.
Answer:
(a) Loudness is determined by the amplitude of the sound wave. Higher the amplitude, higher will be the loudness.
(b) Frequency determines the pitch of the 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 the factors speed of sound wave depends upon?
Q 6.
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 7.
What are ultrasonics?
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.
How does sound travel in gases and liquids as longitudinal or as transverse waves?
Q 11.
What is speed of sound in air?
Q 12.
Calculate the wavelength of a sound wave whose frequency is 220 Hz and speed is
440 m/s in a given medium.
Q 13.
Obtain a relation between speed,frequency and wavelength of a wave.
Q 14.
Fill in the blanks :
Sound, compressional waves in springs are examples of _____________.
Q 15.
What is a wave number?
Q 16.
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 17.
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 18.
Explain how sound is produced by your school bell ?
Q 19.
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 20.
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 21.
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 22.
Why are sound waves called mechanical waves ?
Q 23.
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 24.
Why do we use upholstered seats in theatres and halls ?
Q 25.
Try to imagine what you would feel, what sort of person you would be,had you been born totally deaf.
Q 26.
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 27.
Fill in the blanks :
Full form of SONAR is __________________________.
Q 28.
Fill in the blanks :
v = ? × ?
Q 29.
What is a mechanical wave?
Q 30.
How does the sound produced by a vibrating object in a medium reach your ear?
Q 31.
Why transverse wave does not travel through air or gases?
Q 32.
What are wavelength, frequency, time period and amplitude of a sound wave?
Q 33.
Give an application use of ultrasonics.
Q 34.
What type of wave is represented by density- distance graph?
Q 35.
What is the audible range of the average human ear ?
Q 36.
Explain the working and application of a sonar.
Q 37.
What propagates along with the waves ?
Q 39.
Discuss the structure of human ear from auditory aspect only.
Q 40.
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 41.
If 20 waves are produced per second, what is the frequency in hertz?
Q 42.
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 43.
What is the difference between an echo and a reverberation ?
Q 44.
On what factors does the speed of sound in a material depend ?
Q 45.
Fill in the blanks :
Number of oscillations completed by the oscillator in one second is known as ___________.
Q 46.
Fill in the blanks :
The product of wavelength of wave and its frequency gives _____________.
Q 47.
Why sound waves are called mechanical waves?
Q 48.
What type of waves can travel in vacuum? Give example(s).
Q 49.
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 50.
The sonic boom of an aircraft has a time period of 0 00005 s.Calculate the frequency of the sound produced.
