Physics

Sound

Question:

A hospital uses an ultrasonic scanner to locate tumours in a tissue.What is the wavelength of sound in a tissue in which the speed of sound is 1.7 km/s ? The operating frequency of the scanner is 4.2 MHz.

Answer:

4 x10-4 m
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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.

What is infrasonic? Give an example.

Q 15.

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

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.

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 22.

What are the factors speed of sound wave depends upon?

Q 23.

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

Q 24.

What are transverse waves ?

Q 25.

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 26.

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

Q 27.

Distinguish between loudness and intensity of sound.

Q 28.

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

Q 29.

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

Q 30.

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

Q 31.

Can sound wave travel in vacuum?

Q 32.

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 33.

Give an application use of ultrasonics.

Q 34.

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 35.

What is sound and how is it produced ?

Q 36.

is sound wave called a longitudinal wave ?

Q 37.

What is sound barrier ?

Q 38.

What is a tone ?

Q 39.

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

Q 40.

What is the minimum distance of the obstacle from the source of sound for hearing distinct echo ?

Q 41.

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

Q 42.

How can you make a building sound proof ?

Q 43.

What are the characteristics of a sound ? Discuss each one of them briefly.

Q 44.

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

Q 45.

Fill in the blanks :
When we hear music, the medium through which the sound transmitted is __________ (solid, liquid, gas)

Q 46.

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 47.

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 48.

Fill in the blanks :
Waves transport _________ not matter.

Q 49.

Fill in the blanks :
In a _____________ wave the particles of the medium oscillate in the direction in which the wave travels.

Q 50.

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