Question:
Why transverse wave does not travel through air or gases?
Answer:
In transverse waves, the particles of the medium vibrate perpendicular to the direction of propagation of the wave. The gas particles are loosely packed and compressible. The gas particles do not vibrate in perpendicular direction to the direction of propagation of sound.
Sound
Q 1.
What are ultrasonics?
Q 2.
What are the factors speed of sound wave depends upon?
Q 3.
What is a wave number?
Q 4.
How does sound travel in gases and liquids as longitudinal or as transverse waves?
Q 5.
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 6.
How is sound propagated through a material medium ? What is wave motion ?
Q 7.
Fill in the blanks :
v = ? × ?
Q 8.
How are compressions and rarefactions produced near a source of sound ?
Q 9.
Fill in the blanks :
The product of wavelength of wave and its frequency gives _____________.
Q 10.
Explain how sound is produced by your school bell ?
Q 11.
What is audible range ?
Q 12.
What propagates along with the waves ?
Q 13.
Why do we use upholstered seats in theatres and halls ?
Q 14.
What are wavelength, frequency, time period and amplitude of a sound wave?
Q 15.
What is infrasonic? Give an example.
Q 16.
Give an application use of ultrasonics.
Q 17.
Explain the working and application of a sonar.
Q 18.
What type of waves can travel in vacuum? Give example(s).
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.
What type of wave is represented by density- distance graph?
Q 21.
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 22.
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 23.
What is the difference between an echo and a reverberation ?
Q 24.
Sounds we hear inform us of the state of world around us,especially of that part of it which our other senses,such as touch and sight,cannot reach.Illustrate this with appropriate examples.
Q 25.
Why transverse wave does not travel through air or gases?
Q 26.
How are the wavelength and frequency of a sound wave related to its speed?
Q 27.
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 28.
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 29.
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 30.
How are the wavelength and frequency of a sound wave related to its speed ?
Q 31.
What is the audible range of the average human ear ?
Q 32.
Obtain a relation between speed,frequency and wavelength of a wave.
Q 33.
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 34.
A stone is dropped from the top of a tower 500 m high into a pond of water at the base of the tower.When is the splash heard at the top ? Given,g = 10
and speed of sound = 340 m/s.
Q 35.
How can you make a building sound proof ?
Q 36.
What is sonic boom and when is it heard ?
Q 37.
Fill in the blanks :
Ripples waves on water surface are example of ____________.
Q 38.
Fill in the blanks :
Sound, compressional waves in springs are examples of _____________.
Q 39.
What are wavefronts?
Q 40.
What is reverberation?
Q 41.
Demonstrate an activity to show that sound requires a medium to travel.
Q 42.
Distinguish between loudness and intensity of sound.
Q 43.
A boat anchor is rocked by waves whose consecutive crests are 100 m apart.If the wave speed of the moving crests is 20 m/s,calculate the frequency at which the boat rocks.
Q 44.
A sound wave has a frequency of 2
kHz and wavelengtl 35 cm.How long will it take to travel 1.5 km ?
Q 45.
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 46.
Deaf people can be made to dance to music.Explain how ?
Q 47.
Fill in the blanks :
Number of oscillations completed by the oscillator in one second is known as ___________.
Q 48.
Fill in the blanks :
In the case of a ___________ wave, distance between two consecutive condensations or rarefactions is known as wavelength.
Q 49.
When you shout in front of a hill,your own shout is repeated.Explain.
Q 50.
How can you show that sound waves are longitudinal waves ?
