Question:
Fill in the blanks :
In the case of a ___________ wave, distance between two consecutive condensations or rarefactions is known as wavelength.
Sound
Q 1.
What is audible range ?
Q 2.
What are the factors speed of sound wave depends upon?
Q 3.
What are ultrasonics?
Q 4.
What is speed of sound in air?
Q 5.
How is sound propagated through a material medium ? What is wave motion ?
Q 6.
What is a wave number?
Q 7.
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 8.
How are the wavelength and frequency of a sound wave related to its speed ?
Q 9.
What propagates along with the waves ?
Q 10.
How are compressions and rarefactions produced near a source of sound ?
Q 11.
What is infrasonic? Give an example.
Q 12.
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 13.
How does sound travel in gases and liquids as longitudinal or as transverse waves?
Q 14.
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 16.
Calculate the wavelength of a sound wave whose frequency is 220 Hz and speed is
440 m/s in a given medium.
Q 17.
Why do we use upholstered seats in theatres and halls ?
Q 18.
What are wavelength, frequency, time period and amplitude of a sound wave?
Q 19.
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 20.
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 21.
Explain how sound is produced by your school bell ?
Q 22.
Fill in the blanks :
v = ? × ?
Q 23.
If 20 waves are produced per second, what is the frequency in hertz?
Q 24.
Give an application use of ultrasonics.
Q 25.
Which wave characteristics determine the
(a) Loudness (b) pitch of sound?
Draw two different waveforms and mark these characteristics on it.
Q 26.
Why are sound waves called mechanical waves ?
Q 27.
By how much does the speed of sound increase with rise of temperature ?
Q 28.
Obtain a relation between speed,frequency and wavelength of a wave.
Q 29.
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 30.
Fill in the blanks :
Sound, compressional waves in springs are examples of _____________.
Q 31.
What is a mechanical wave?
Q 32.
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 33.
What type of wave is represented by density- distance graph?
Q 34.
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 35.
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 36.
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 37.
Fill in the blanks :
Ripples waves on water surface are example of ____________.
Q 38.
Fill in the blanks :
In a _____________ wave the particles of the medium oscillate in the direction in which the wave travels.
Q 39.
Fill in the blanks :
Full form of SONAR is __________________________.
Q 40.
Why sound waves are called mechanical waves?
Q 41.
How does the sound produced by a vibrating object in a medium reach your ear?
Q 42.
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 43.
The frequency of a source of sound is 100 Hz.How many times does it vibrate in a minute ?
Q 44.
Try to imagine what you would feel, what sort of person you would be,had you been born totally deaf.
Q 45.
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 46.
Fill in the blanks :
In the case of a ___________ wave, distance between two consecutive condensations or rarefactions is known as wavelength.
Q 47.
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 48.
Can sound wave travel in vacuum?
Q 49.
What type of waves can travel in vacuum? Give example(s).
Q 50.
Why transverse wave does not travel through air or gases?
