Question:
How does sound travel in gases and liquids as longitudinal or as transverse waves?
Answer:
As longitudinal waves
Sound
Q 1.
What are the factors speed of sound wave depends upon?
Q 2.
What is audible range ?
Q 3.
What are ultrasonics?
Q 4.
How is sound propagated through a material medium ? What is wave motion ?
Q 5.
What is speed of sound in air?
Q 6.
How are compressions and rarefactions produced near a source of sound ?
Q 7.
What is a wave number?
Q 8.
What is infrasonic? Give an example.
Q 9.
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 10.
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 11.
How are the wavelength and frequency of a sound wave related to its speed ?
Q 12.
What propagates along with the waves ?
Q 13.
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 14.
How does sound travel in gases and liquids as longitudinal or as transverse waves?
Q 15.
Calculate the wavelength of a sound wave whose frequency is 220 Hz and speed is
440 m/s in a given medium.
Q 17.
What are wavelength, frequency, time period and amplitude of a sound wave?
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.
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 20.
Why do we use upholstered seats in theatres and halls ?
Q 21.
Fill in the blanks :
v = ? × ?
Q 22.
If 20 waves are produced per second, what is the frequency in hertz?
Q 23.
Give an application use of ultrasonics.
Q 24.
Explain how sound is produced by your school bell ?
Q 25.
Why are sound waves called mechanical waves ?
Q 26.
By how much does the speed of sound increase with rise of temperature ?
Q 27.
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 28.
Fill in the blanks :
Sound, compressional waves in springs are examples of _____________.
Q 29.
What is a mechanical wave?
Q 30.
Which wave characteristics determine the
(a) Loudness (b) pitch of sound?
Draw two different waveforms and mark these characteristics on it.
Q 31.
Obtain a relation between speed,frequency and wavelength of a wave.
Q 32.
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 33.
Fill in the blanks :
In a _____________ wave the particles of the medium oscillate in the direction in which the wave travels.
Q 34.
Why sound waves are called mechanical waves?
Q 35.
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 36.
How does the sound produced by a vibrating object in a medium reach your ear?
Q 37.
What type of wave is represented by density- distance graph?
Q 38.
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 39.
A ship sends out ultrasound that returns from the seabed and is detected after 3.42 s.If the speed of the ultrasound through sea water is 1531 m/s,what is the distance of the seabed from the ship ?
Q 40.
Today our life is richer and fuller of music than it was yesterday,and much of this is due to progress in engineering.What will happen to human feelings when the sea of knowledge spreads further ?
Q 41.
Fill in the blanks :
If a body repeats its back and forth, to and fro or up and down motion along a certain path, about a fixed point, in a certain time interval then the motion of such objects is said to be _____________.
Q 42.
Fill in the blanks :
Ripples waves on water surface are example of ____________.
Q 43.
Fill in the blanks :
In the case of a ___________ wave, distance between two consecutive condensations or rarefactions is known as wavelength.
Q 44.
Fill in the blanks :
Full form of SONAR is __________________________.
Q 45.
Why transverse wave does not travel through air or gases?
Q 46.
The frequency of a source of sound is 100 Hz.How many times does it vibrate in a minute ?
Q 47.
What is an echo ? How is it formed ?
Q 48.
Try to imagine what you would feel, what sort of person you would be,had you been born totally deaf.
Q 49.
Fill in the blanks :
Number of oscillations completed by the oscillator in one second is known as ___________.
Q 50.
Fill in the blanks :
The product of wavelength of wave and its frequency gives _____________.
