question from sound waves for competitive exam

sound waves

 some basic definitions

💢The waves which required no medium for their propagation or production are called 

                                         ➡️ electromagnetic waves

💢The waves which can be propagated or produced only in a material medium are called

                                                   ➡️ mechanical waves

💢How many types of mechanical waves two type

                                   ➡️ longitudinal and transverse

💢The particles of the medium vibrate perpendicular to the direction of propagation of wave that wave is called

                                 ➡️ transverse mechanical wave.

 💢the particle of the medium vibrate  in the direction of the propagation of wave ,that wave is called 

                              ➡️longitudinal mechanical waves

💢The maximum displacement of A vibrating particle of medium from its mean position is called 

                                                                  ➡️amplitude.

💢The number of vibration completed by a particle in one second is known as 

                                                                   ➡️frequency.

💢The frequency of sound waves can be expressed in 

                                                     ➡️cycles per second.

💢The product of the time period of a wave and its frequency is

                                                                      ➡️unity 

🌑relation between frequency and time period is inversely proportional






💢Examples of electromagnetic waves

                                                         ➡️ light and heat


 💢the unit of frequency is

                                                              ➡️Hertz





💢Sound waves is an example of

                           ➡️ longitudinal mechanical waves.


💢The sounds having a frequency of 20 hertz to 20000 Hertz are known as 

                                         ➡️audible or sound waves.






💢Sound waves  of wavelength greater than that of audible sound are called

                                                            ➡️ Sonic waves.




💢The velocity of sound less than 20 heart is known as 
                                                     ➡️infrasonic waves.





💢The infrasonic Waves produced by 

               ➡️earthquakes ,volcanic, eruption ,Ocean waves  elephant and whales.


💢The velocity of sound more than 20000 hertz is known as 

                                                    ➡️Ultrasonic waves.


Ultrasonic waves are those waves which human beings cannot hear.





💢Ultrasonic waves are used for

                      ➡️ sending signals ,measuring the depth of sea ,cleaning clothes and in ultrasonography.

Important question from sound waves

💢Sound can travel through➡️ solid liquid and gases.

💢Sound waves cannot passes through➡️ vacuum

💢Speed of sound is maximum in ➡️solid

💢Speed of sound is minimum in ➡️gases

💢Speed of sound is Greater in solids than in gases because 

                        ➡️the elasticity of solids is very high.

💢The speed of sound basically depends upon

                                             ➡️ elasticity and density.

💢when sound enters from one medium to another medium its speed and wavelength changes but

                                 ➡️ frequency remains constant.

💢By increasing or decreasing the pressure the speed of sound remain 

                                                                      ➡️constant

💢With the rise of temperature the speed of sound is
                                                                 ➡️ increases.

💢The speed of sound is more in humid air than in dry air because
                     ➡️ the density of humid air is less than the density of dry air.

💢The speed of sound in air increases by 0.61 M/S  when the temperature is increases by ➡️1°C

💢The speed of sound in air➡️ 332 m/s

💢The speed of sound in water➡️ 1483 M /s

💢The speed of sound in iron➡️ 5130 M/s

💢The unit used to measure loudness of sound is 

                                                                    ➡️decibel

💢What is the maximum limit of sound intensity in decibel units beyond  above which is harmful to human ear

                                                                   ➡️85 decibel.

💢The loudness of sound depends upon

                                                                 ➡️ amplitude.

💢Pitch of sound depends on

                                      ➡️ frequency of sound waves.

💢The quality of sound produced by an instrument depends on
   
                                         ➡️the number of overtones.

💢The speed of supersonic wave is measured in

                                                          ➡️ Mach number.

💢Mach number is the ratio of

             ➡️ velocity of sound and velocity of a body.

💢If Mach number more than 1, the body is called 

                                                                 ➡️Supersonic

💢If Mach number less than 1 the body is called 

                                                                  ➡️subsonic.

💢if Mach number more than 5 the body is called 

                                                                ➡️hypersonic.

💢Supersonic air planes create a shock wave  called

                                                              ➡️ sonic boom.

💢Bats can fly in the dark because they are guided by
                    ➡️ Ultrasonic waves produced by them.

💢The same notes being played on Sitar and Veena differ in

                                                                     ➡️ quality.

The quality of a musical note depends upon its harmonic content.

💢A group of soldiers on a bridge are advised not to walk in steps because 

     ➡️their movement causes the bridge to vibrate. 

💢The technique used to transmit audio signals in television broadcast is

                                            ➡️frequency modulation.










 💢ultraviolet light of Sun's radiation is prevented from reaching the earth's atmosphere by the layer of
                                                                         ➡️ ozone.










💢When a stone is dropped on the surface of still water the waves produced are 

           ➡️partly transverse and partly longitudinal.
















💢The waves used for a communication artificial satellite are 

                                                            ➡️microwaves













💢The structure of solids is investigated by using 

                                                                       ➡️X-rays








💢X-rays absorption will be maximum for the sheets of

                                                                            ➡️ lead.









💢X-rays are heavily absorbed by lead  atoms ,but to obtain X-rays photograph of stomach Barium sulphate is usually given to the patient instead  of lead salt, because 

                               ➡️lead salts are more poisonous.

💢The Echo is produced by the sound waves due to

                                                  ➡️ reflection of sound.

💢An echo will be heard if the minimum distance between the source of sound and obstacle is

                                                                      ➡️ 17 m .

💢The Echo  will be heard  if the original sound reflected by an obstacle is 

                                                            ➡️0.1 second.

💢At the moon the Echo is not heard  due to 

                                            ➡️absence of atmosphere.

💢SONAR stands for

                           ➡️ sound Navigation and Ranking. 

💢SONAR is based on 

                                             ➡️the principle of Echo.

💢Where the Sonar use  

                                    ➡️measure the depth of  a sea.

💢The Doppler's Effect is applicable for

                      ➡️ space waves , sound waves and light waves.

💢The pitch of frequency of the siren of a coming train  appears to be increasing because of  

                                                       ➡️doppler's effect.

💢Doppler Effect is independent of 

                ➡️distance between source and observer.






💢X-rays are vigorously used in the various 

➡️surgical diagnosis of bone fractures or the occurrence of disease in lungs Kidneys etc.in medical hospital and for various industrial purpose.

💢Gamma rays has maximum penetrating power and it is  utilized in 

      ➡️nuclear reaction and artificial radioactivity.








💢Infra -red radiation are utilised in the

➡️photography of the object behind the mist and fog.
 it is also used to warm the patients in hospital .  

 in TV remote also.










💢radio waves are 

                     ➡️utilised in Radio, TV and telephone .