Question:
Obtain a relation between speed,frequency and wavelength of a wave.
Answer:
Refer to Art.6.11,Page 330.
Sound
Q 1.
Fill in the blanks :
v = ? × ?
Q 2.
What are the factors speed of sound wave depends upon?
Q 3.
Why do we use upholstered seats in theatres and halls ?
Q 4.
What propagates along with the waves ?
Q 5.
What are ultrasonics?
Q 6.
How is sound propagated through a material medium ? What is wave motion ?
Q 7.
Explain how sound is produced by your school bell ?
Q 8.
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 9.
What are wavefronts?
Q 10.
Fill in the blanks :
The product of wavelength of wave and its frequency gives _____________.
Q 11.
What is a wave number?
Q 12.
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 13.
Explain how the human ear works.
Q 14.
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 15.
Obtain a relation between speed,frequency and wavelength of a wave.
Q 16.
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 17.
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 18.
Explain the working and application of a sonar.
Q 19.
What travels faster : a rifle bullet or the sound of the shot fired from it ?
Q 20.
How does sound travel in gases and liquids as longitudinal or as transverse waves?
Q 21.
Distinguish between loudness and intensity of sound.
Q 22.
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 23.
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 24.
What is audible range ?
Q 25.
What is the difference between an echo and a reverberation ?
Q 26.
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 27.
Try to imagine what you would feel, what sort of person you would be,had you been born totally deaf.
Q 28.
What is Sound? Why it is important for us?
Q 29.
Why transverse wave does not travel through air or gases?
Q 30.
Calculate the wavelength of a sound wave having a frequency 300 Hz and speed 330 m/s.
Q 31.
Fill in the blanks :
If a body repeats its motion, within fix interval of time, along a certain path, about a fixed point, it is said to have ____________.
Q 32.
Fill in the blanks :
RADAR (Radio Detection And Ranging) works on _____________ principle which is used to determine the velocities and movement of aircrafts.
Q 33.
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 34.
What is infrasonic? Give an example.
Q 35.
A periodic longitudinal Wave is sent on a slinky.The wave proceeds at a speed of 48 m/s and each particle oscillates at a frequency of 12 Hz.Calculate the minimum separation between the positions where the slinky is most compressed.
Q 36.
Guess which has a higher pitch : a guitar or a car horn ?
Q 37.
How are the wavelength and frequency of a sound wave related to its speed ?
Q 38.
Write the name of the wave which propagates in terms of compressions and rarefactions.
Q 39.
How are compressions and rarefactions produced near a source of sound ?
Q 40.
What are wavelength, frequency, time period and amplitude of a sound wave?
Q 41.
Give an application use of ultrasonics.
Q 42.
What type of wave is represented by density- distance graph?
Q 43.
What is the audible range of the average human ear ?
Q 44.
What do you mean by reverberation and reverberation time ? How is reverberation controlled ?
Q 45.
Fill in the blanks :
Waves transport _________ not matter.
Q 46.
Write differences between Transverse waves and Longitudinal waves.
Q 48.
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 49.
The sonic boom of an aircraft has a time period of 0 00005 s.Calculate the frequency of the sound produced.
Q 50.
Radio Ceylon broadcasts at 25 m.What is the frequency of the station ?
