Ch-11: Sound

Ch-11: Sound 

Here this post contains Short Question and Answers of Chapter 11: "Sound". Learn these question answers and other related stuff for exam preparation. 

A sound is a type of energy, very much like power, intensity or light. Sound is one of the significant feelings of the human body. A few sounds are wonderful, and some are irritating. We are exposed to different kinds of sound all time. Sound is a vibration that spreads as an acoustic wave, through a transmission medium

Q-1:	Why sound waves are called mechanical waves?
Ans:	Sound waves are called mechanical waves because they require material medium for their propagation.
Q-2:	What is speed?
Ans:	The distance covered in unit time is called speed.
Q-3:	Difference Between the loudness and intensity of sound.
Ans:	Loudness: i. Characteristics of sound by which we can distinguish between loud and faint Sounds is called loudness. ii. It is not physical quantity.
Q-4:	Difference between frequency and pitch.
Ans:	Frequency is a physical quantity which gives number of vibrations per second whereas pitch is a perceptual quantity which depends upon the listener, in fact our ears detects the pitch not the frequency.
Q-5:	Explain that noise is a nuisance?
Ans:	Noise is a nuisance because it causes offence annoyance, trouble or injury.
Q-6:	Difference between echo and reflection of sound?
Ans:	The echo is formed through reflection but the reflection does not form echo. All sounds reflect back but it is not necessary that all reflections produce echo.
Q-7:	Define loudness? On what factors loudness depends.
Ans:	"Loudness is the characteristics of sound by which loud and faint sounds cab be distinguished". Loudness depends upon a number of factors. Such as. i. Amplitude of the vibrating body ii. Araa of the vibrating body iii. Distance from the vibrating body iv. Physical condition of ear.
Q-8:	Why ultrasound is useful in medical field?
Ans:	Ultrasonic waves carry more energy and short wavelength therefore ultrasonic waves are used to diagnose and treat different ailments.
Q-9:	What is frequency.
Ans:	The number of vibration s per cycle of a vibrating body n one second is called frequency.
Q-10:	What is diaphragm?
Ans:	the chest piece consists of a plastic disc called diaphragm in stethoscope.
Q-11:	Define wavelength of sound wave.
Ans:	Distance between two consecutive compressions or rarefactions is called the wavelengths of sound wave.
Q-12:	Which instrument is used to see the sound waves?
Ans:	By using an"Oscilloscope" we can see sound waves.
Q-13:	Define intensity and its unit.
Ans:	Sound energy passing per second through a unit area held perpendicular to the direction of propagation of sound waves is called intensity of sound.
Q-14:	Difference between Quality and pitch.
Ans:	the property of sound by which we can distinguish between two sounds of same loudness and pitch is called quality.
Q-15:	Define echo of sound.
Ans:	When sound is incident on the surface of a medium it bounces back into the first medium, This phenomenon is called echo or reflection of sound.
Q-16:	What are sources of noise pollution?
Ans:	Transportation equipment, heavy machinery, loud vehicles horns and alarms are the source of noise pollution.
Q-17:	Why the voice of women is shriller than that of men?
Ans:	The frequency of the voice of ladies is higher than that of men.There fore, the voice of ladies is shrill and of high pitch.
Q-18:	What is audible frequency range?
Ans:	The range of the frequencies which a human ear can hear is called the audible frequency range.
Q-19:	What is musical sound?
Ans:	Sounds which are pleasant to our ears are called musical sounds. e.g. sounds of guitar and violin.
Q-20:	What is SONAR?
Ans:	SONAR is "sound navigation and ranging". It is a technique used to estimate the distance of object from the ocean surface.
Q-21:	On what factors pitch depends.
Ans:	It depends upon the frequency. A higher pitch menas higher frequcney and vice verse.
Q-22:	Of what kind sound waves are produced by tuning fork?
Ans:	With the vibration of tuning fork compressional waves are produced, because it vibrate about its mean position.
Q-23:	How sound is produced in laboratory?
Ans:	Sound is produced in laboratory with the tuning fork by striking it to the rubber pad due to which vibrations are produced and sound is generated due to vibrations.
Q-24:	Define Compression.
Ans:	When the prongs of tuning fork move right and exert pressure on the layer of air. This pressure due to which air particles are compressed is called compression
Q-25:	What is audible frequency range?
Ans:	We can hear the sound of frequency lying between 20 Hz to 20,000 Hz. This is called audible frequency range
Q-26:	What is meant by ultrasonic? Give its two uses.
Ans:	The sound waves which have frequency more than 20,000 Hz is called ultrasonic. Uses (1) It helps us in industry to find cracks in machinery (2) Depth of an ocean can also be measured by using ultrasonic.
Q-27:	How can we find speed of sound? Write its formula.
Ans:	With the help of resonance tube we can determine the speed of sound. The formula use to calculate speed of sound is v = √γRTM.
Q-28:	How you can explain that greater the surface area greater is sound?
Ans:	Greater the surface area of vibrating body greater is the sound produced. For example the bell of school has greater area, so its sound is louder while the bell used in home has less area so fainter sound is produced.
Q-29:	Write about the hearing process.
Ans:	Sound is accepted by external ear and sends it to the eardrum. Oval window accept these vibration and send it to the cochlea in the inner ear, from here these waves are sent to brain through auditory nerves.
Q-30:	What is meant by resonance?
Ans:	The phenomena in which there is remarkable increase in amplitude and hence loudness of the sound when the frequency of air column becomes equal to that tuning fork is called resonance
Q-31:	What is silent whistle?
Ans:	Some people use silent whistle to call dogs whose frequency lies between 20.000 Hz to 25.000 Hz. It is silent for human but not for dogs because their audible frequency range is much more than humans audible frequency range
Q-32:	Name three parts of human ear.
Ans:	i) Outer ear ii) Middle ear iii) Inner ear
Q-33:	What do you mean by rarefaction?
Ans:	When the prongs of tuning fork move toward left the pressure on the layer to the right is less due to this rarefaction is produced.
Q-34:	How is sound produced?
Ans:	Sound can be generted by the vibration of the body.
Q-35:	Is any medium required for propagation of sound?
Ans:	Yes, any material medium is required for propagation of sound, i.e solid, liquid and gas
Q-36:	Write the name of characteristic of sound?
Ans:	There are five characteristics of sound: i. Loudness of sound ii. Intensity of sound iii. Pitch iv. Quality of sound v. Music and noise
Q-37:	Define loudness?
Ans:	It is characteristic of sound due to which we can distinguish between louder and fainter sound is called loudness.
Q-38:	What do you mean by intensity of sound?
Ans:	Energy flowing per second through a unit area held perpendicular to the direction of sound waves is called intensity of sound.
Q-39:	Define pitch?
Ans:	It is the characteristics of sound due to which two sounds of same loudness and pitch are distinguished from each other is called quality. It depends upon wave form.
Q-40:	Distinguish between noise and musical sound?
Ans:	The sound which has pleasant effect on ear is called musical sound. The sound which has jarring effect is called noise. The frequency and amplitude of musical sound chahnge in a regular manner. The frequency and amplitude of noise change in an irregular manner.