Question:
Deaf people can be made to dance to music.Explain how ?
Answer:
If there is nothing wrong with the internal ear,deaf people can listen to music.This can be made possible by placing one end of a rod on a piano (or any other musical instrument) in such a way that it does not obstruct playing upon it.The other end of the rod can be gripped in the teeth.The music would reach the auditory nerve via rod and bones of the head.
Sound
Q 1.
What are the factors speed of sound wave depends upon?
Q 2.
Fill in the blanks :
v = ? × ?
Q 3.
Why do we use upholstered seats in theatres and halls ?
Q 4.
What are ultrasonics?
Q 5.
What propagates along with the waves ?
Q 6.
What are wavefronts?
Q 7.
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 8.
Obtain a relation between speed,frequency and wavelength of a wave.
Q 9.
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 10.
What is infrasonic? Give an example.
Q 11.
Explain how sound is produced by your school bell ?
Q 12.
Explain how the human ear works.
Q 13.
How is sound propagated through a material medium ? What is wave motion ?
Q 14.
Fill in the blanks :
The product of wavelength of wave and its frequency gives _____________.
Q 15.
What is a wave number?
Q 16.
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 17.
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 18.
How does sound travel in gases and liquids as longitudinal or as transverse waves?
Q 19.
What travels faster : a rifle bullet or the sound of the shot fired from it ?
Q 20.
Try to imagine what you would feel, what sort of person you would be,had you been born totally deaf.
Q 21.
What type of wave is represented by density- distance graph?
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.
Calculate the wavelength of a sound wave having a frequency 300 Hz and speed 330 m/s.
Q 24.
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 25.
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 26.
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 27.
What is audible range ?
Q 28.
What are wavelength, frequency, time period and amplitude of a sound wave?
Q 29.
Distinguish between loudness and intensity of sound.
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.
Explain the working and application of a sonar.
Q 33.
Write the name of the wave which propagates in terms of compressions and rarefactions.
Q 34.
Fill in the blanks :
RADAR (Radio Detection And Ranging) works on _____________ principle which is used to determine the velocities and movement of aircrafts.
Q 35.
Can sound wave travel in vacuum?
Q 36.
Give an application use of ultrasonics.
Q 37.
Guess which has a higher pitch : a guitar or a car horn ?
Q 38.
Distinguish between music and noise.
Q 39.
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 40.
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 41.
What is Sound? Why it is important for us?
Q 42.
Why transverse wave does not travel through air or gases?
Q 43.
If 20 waves are produced per second, what is the frequency in hertz?
Q 44.
A person clapped his hands near a cliff and heard the echo after 5 s.What is the distance of the cliff from the person if the speed of the sound,v is taken as 346 m/s ?
Q 45.
What are infrasonics ?
Q 46.
What is the minimum distance of the obstacle from the source of sound for hearing distinct echo ?
Q 47.
What is the difference between an echo and a reverberation ?
Q 48.
Fill in the blanks :
The distance between two consecutive compressions or two consecutive rarefactions is called the ______________.
Q 49.
Fill in the blanks :
Existence of sound waves in an auditorium due to multiple reflections suffered by the walls and ceiling is called ____________.
Q 50.
Write differences between Transverse waves and Longitudinal waves.
