Physics

Sound

Question:

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 ?

Answer:

(i) Musical notes will be formed exactly like the human voice by blending pure tones.They will give them a human quality and vital power Instrumental music will be able to speak,laugh and cry in the direct meaning of these words.(ii) Music synthesizers will obey man and give the composer an unprecedented freedom of creation.(iii) The performing artist will be able to control the new instruments with his eyes and thoughts rather than by his lips or hands,as the violinist,the trumpeter or the pianist does today.He will be both a physicist and a poet and will make a happy union of knowledge and inspiration.
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Sound

Q 1.

What is speed of sound in air?

Q 2.

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 3.

What is reverberation?

Q 4.

What is echo?

Q 5.

Fill in the blanks :
The principle on which stethoscope works is _____ (reflection/ multiple reflection)

Q 6.

Distinguish between loudness and intensity of sound.

Q 7.

What type of wave is represented by density- distance graph?

Q 8.

What is Sound? Why it is important for us?

Q 9.

What are wavelength, frequency, time period and amplitude of a sound wave?

Q 10.

What are ultrasonics?

Q 11.

Fill in the blanks :
A ________ (pulse/wave) is a disturbance which is sudden and lasts for a short duration of time.

Q 12.

Fill in the blanks :
In the case of ____________ wave, distance between two consecutive crests or troughs is known as wavelength.

Q 13.

Fill in the blanks :
RADAR (Radio Detection And Ranging) works on _____________ principle which is used to determine the velocities and movement of aircrafts.

Q 14.

Fill in the blanks :
Loudness of sound is measured in ___________.

Q 15.

What is infrasonic? Give an example.

Q 16.

What is a mechanical wave?

Q 17.

What is the audible range?

Q 18.

Fill in the blanks :
Sound having frequency less than 20Hz is known as ___________.

Q 19.

Radio Ceylon broadcasts at 25 m.What is the frequency of the station ?

Q 20.

Draw a curve showing density or pressure variations with respect to distance for a disturbance produced by sound.Mark the position of compression and rarefaction on this curve.Also define wavelengths and time period using this curve.

Q 21.

What are the factors speed of sound wave depends upon?

Q 22.

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 23.

How does the sound produced by a vibrating object in a medium reach your ear ?

Q 24.

Distinguish between loudness and intensity of sound.

Q 25.

How is sound propagated through a material medium ? What is wave motion ?

Q 26.

What are transverse waves ?

Q 27.

What do you mean by reverberation and reverberation time ? How is reverberation controlled ?

Q 28.

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 29.

Fill in the blanks :
Full form of SONAR is __________________________.

Q 30.

Can sound wave travel in vacuum?

Q 31.

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 32.

Give an application use of ultrasonics.

Q 33.

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 34.

What is sound and how is it produced ?

Q 35.

is sound wave called a longitudinal wave ?

Q 36.

What is sound barrier ?

Q 37.

By how much does the speed of sound increase with rise of temperature ?

Q 38.

There are no echoes produced in small living rooms.Explain why echoes are produced only in large galleries and halls.

Q 39.

How can you make a building sound proof ?

Q 40.

What is SONAR ? How is it used to detect an underwater object and measure its distance

Q 41.

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 42.

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 43.

Fill in the blanks :
Waves transport _________ not matter.

Q 44.

Fill in the blanks :
In the case of a ___________ wave, distance between two consecutive condensations or rarefactions is known as wavelength.

Q 45.

Fill in the blanks :
Audible sound range is _________ to _____________.

Q 46.

Fill in the blanks :
If the time interval between original sound and reflected sound is more than 1/10 second then original sound and reflected sound can be heard clearly. This reflected sound is known as _______.

Q 47.

Fill in the blanks :
v = ? × ?

Q 48.

How does sound travel in gases and liquids as longitudinal or as transverse waves?

Q 49.

What is a longitudinal wave?

Q 50.

Why sound waves are called mechanical waves?