Audible, infra and ultra sound with its application - class-XI

The relationship between frequency, speed of sound and wavelength of a sound wave is given as 

The generally accepted standard range of audible frequencies is 20 to 20,000 Hz, although the range of frequencies individuals hear is greatly influenced by environmental factors.
Hence, 100 Hz is an audible sound.

The generally accepted standard range of audible frequencies is 20 to 20,000 Hz, although the range of frequencies individuals hear is greatly influenced by environmental factors.
Hence, 1000 Hz is an audible sound.

The human auditory system is sensitive to frequencies from about 20 Hz to a maximum of around 20,000 Hz, although the upper hearing limit decreases with age. Within this range, the human ear is most sensitive between 2000 and 5000 Hz, largely due to the resonance of the ear canal and the transfer function of the ossicles of the middle ear. The high sensitivity region at 2000 - 5000 Hz is very important for the understanding of speech.
Hence, the statement is true.

We have , 

The generally accepted standard range of audible frequencies is 20 to 20,000 Hz, although the range of frequencies individuals hear is greatly influenced by environmental factors. Frequencies below 20 Hz are generally felt rather than heard, assuming the amplitude of the vibration is great enough. Frequencies above 20,000 Hz can sometimes be sensed by young people. High frequencies are the first to be affected by hearing loss due to age and/or prolonged exposure to very loud noises.
The range of frequency within which the sound can be heard by a human being is called the audible range of frequency.

We have the formula,

The audible frequency range for human ear is from 20Hz to 20,000Hz , as out of the given frequencies , only frequency of 15000Hz lies in audible range , therefore it can be heard by human ear .

Wave form of sound is energy.  Sound wave is produced when an object is made to vibrate. Sound needs a medium such as air, water etc.  to travel.  

Waves can be categorised on the basis of frequency as :

Answer is C.

The generally accepted standard range of audible frequencies is 20 Hz to 20,000 Hz, although the range of frequencies individuals hear is greatly influenced by environmental factors. 

A person who has hearing within the normal range can hear sounds that have frequencies between 20 Hz to 20,000  Hz. This frequency range is called audible frequency range. Since the frequency 30,000 Hz is above the audible frequency range human ear cannot audible it clearly.

Human ear can hear sound having frequency range from $20 \ Hz$ to $20 \ kHz$.

Human ear can hear sound having frequency range from  $20 \ Hz$ to $20$ $kHz$.

The audible range of frequency is $20;Hz$ to $20,000;Hz$

The frequency range of human hearing is about 20 Hz to 20 KHz. This range of frequency is known as audible range. Human cannot hear the sound with frequency above or below this audible range. Hence the sound with frequency 30,000 Hz cannot audible to human ear

Velocity is a vector quantity defined as the rate of change of displacement with respect to time, which explicitly specifies both the speed and the direction of motion of a particle at any given instant.

The audible range of frequency is $20;Hz$ to $20,000;Hz$

The audible range of frequency is $20;Hz$ to $20,000;Hz$

The sound intensity of a human whisper has an intensity of approximately $30,dB$.

The range of ultrasonic vibrations is above 20,000 Hz. These are high frequency sound waves beyond the range of human hearing.

Human ear can hear sound having frequency range from $20 \ Hz$ to $20 \ kHz$.

Human ear can hear sound having frequency range from $20 \ Hz$ to $20 \ kHz$.

The human hear responds to sounds with frequencies in the range from 20 Hz to 20,000 Hz. This is called the audible range of the human ear.

the Audible range  of frequency for human ear is 20Hz to 20000Hz 

The audible frequency range for human ear is from 20Hz to 20,000Hz , as out of the given frequencies , only frequency of 50000Hz doesn't lie in audible range , therefore it cannot be heard by human ear .

The human hear can respond to minute pressure variations in the air if they are in the audible frequency range, roughly 20 Hz to 20,000 Hz. The vibrations above or below this range is not audible by human.

Humans cannot hear sound of every frequency. The range of hearing for a healthy young person is 20 Hz to 20,000 Hz. This is called audible range of frequency. So, human can hear sound of frequency 100 Hz.

Some animals like whale, octopus and rhino have special hearing abilities and can hear sounds below $20\ Hz$, i.e., the infrasounds.

Humans can hear sounds having frequencies between the range of $20\ Hz$ and $20,000\ Hz$. The sounds above and below this range are inaudible to humans. The sounds below the range of $20\ Hz$ are called infrasounds and the sounds above the range of $20,000\ Hz$ are called ultrasounds. Both are inaudible to humans.

The range of audible frequency is 20 Hz - 20,000 Hz.
In the first case frequency of the tuning fork will be 200 Hz. 
In second case it will be 60 Hz.
In third case frequency will be 1 Hz ,which is out of the audible frequency range.

Sound of vibrations of pendulum lies in infrasonic range while sound of bees lies in audible range.

Sound is heard only if the body vibrates with a frequency of at least 20 Hz. Frequency of vibration of the pendulum is less than 20 Hz. Hence no sound is heard when the pendulum vibrates or oscillates in air.

The frequency of ultrasonic wave is greater than 20,000 Hz and equal to 107 Hz. These waves are not audible to a human ear but they can be heard by animals and birds.

Ultrasonic sounds are inaudible to humans, hence they are used for various purposes. These waves strike the object of interest and are reflected back. These reflected waves are captured and the object of interest is studied.

It will be audible by the human ear because vibration is produced 200 times/second.
So,frequency = 200 Hz
And the range of audible frequency is 20 Hz - 20,000 Hz.

Animals like dogs, whales, bats, dolphins, etc. can hear sounds of frequencies more than $20,000\ Hz$, i.e., ultrasounds. These sounds are inaudible to humans. However, they are important for these animals as it helps them to locate prey and escape from obstacles.

Has been seen that the behaviour of animals becomes unusual just before the tremor is felt. This is because animals are able to detect infrasonic waves produced at the time of tremor.
Infrasonic waves are waves of frequency less than 20Hz.

Bats can produce ultrasonic waves by flapping their wings.
They can also detect these waves.these waves produced by the bats after reflection from the obstacles like building guide them to  remain away from the obstacles during night with the help of ultrasonic waves.

A sound of frequency 50,000 hertz can be heard by a dog but not by a man. The waves having frequency between 20 Hz - 20,000 Hz are audible frequency of waves.

Infrasonic waves are waves whose frequency is below 20Hz. These sounds are not heard by human ears. Audible sounds are between 20 Hz and 20,000 Hz.

This is because the screams are ultrasonic(above 20,000 hertz) which human ear cannot hear.

Bats can produce ultrasonic waves by flapping their wings.
They can also detect these waves.these waves produced by the bats after reflection from the obstacles like building guide them to  remain away from the obstacles during night with the help of ultrasonic waves.

Ultrasound is used in echocardiography. In this ultrasound are used to construct the image of heart. Ultrasounds and infrasounds are not audible to man. Ultrasound have frequency more than 20 kHz.
Infrasound have frequency below 20 Hz.
Y is infrasound .

The waves having frequency between 20Hz and 20,000Hz are known as sound waves. Thus the audible range of frequency is 20Hz to 20,000Hz.

The range of audible frequency is 20 Hz to 20,000 Hz. In the first case frequency of the tuning fork will be 200Hz. In second case it will be 60Hz and In third case frequency will be 1 Hz ,which is out of the audible frequency range. In fourth case frequency is 450 Hz which is again in the audible range.

Frequencies higher than 20 kHz are called ultrasonic sound or ultrasound. Ultrasound is produced by dolphins, bats and porpoises. Moths of certain families have very sensitive hearing equipment. These moths can hear the high frequency squeaks of the bat and know when a bat is flying nearby, and are able to escape capture. Rats also play games by producing ultrasound.

Ultrasound is used to see what is happening in a nuclear reactor. Ultrasounds and infrasounds are not audible to man. Ultrasound have frequency more than 20 kHz.
Infrasound have frequency below 20Hz.

It will be audible by the human ear because vibration is produced 200 times/second. So,frequency =200Hz. And the range of audible frequency is 20Hz-20,000Hz. 

The human ear can not hear all frequency of sounds. The audible range of the frequency is 20 Hz to 20000 Hz. The human ear is able to hear the sounds those have frequencies in that audible range.   

The low frequency vibration of infrasonic wave is less than $20,Hz$. The pendulum vibrates at this low frequency with a time period of $1$ second.

Bats emit ultrasonic sound waves which bounces back from the objects and enables them to sense an obstruction and also hunt for prey.

The generally accepted standard range of audible frequencies is 20 to 20,000 Hz, although the range of frequencies individuals hear is greatly influenced by environmental factors. Frequencies below 20 Hz are  generally felt rather than heard, assuming the amplitude of the vibration is great  enough. So 5 and 10 Hz both can't be heard by human ear in general.

The frequency of a vibrating pendulum is quite small and less than 20 Hz which is not in the audible range. Hence, it is not heard.

The generally accepted standard range of audible frequencies is 20 to 20,000 Hz, although the range of frequencies individuals hear is greatly influenced by environmental factors. Frequencies below 20 Hz are generally felt rather than heard, assuming the amplitude of the vibration is great enough. So sound with frequency 40,000 Hz can't be heard by human ear in general.

sound needs a medium to travel and to hear a sound it should be in audible range in any medium.

$20\leq $ Audible frequency $\leq 20 kHz$

Dense molecules vibrate at slower speeds. The more dense the string is, the slower it will vibrate, and the lower its frequency will be. Instruments often have strings made of different materials. The strings used for low pitches will be made of a more dense material than the strings used for high pitches. 
The more dense the medium the slower the speed of sound. For example steel is 6000 times more denser than air but 2,000,000 times more elastic than air, so sound travels 16 times faster in steel than in air. 

For hearing a distinct sound, the time interval between  original sound and the reflected one must be at least 0.1 s.

(A) When a guitar string is struck , string is disturbed and the medium (string) particles vibrate perpendicular to the direction of motion disturbance , therefore transverse vibrations are set on the guitar string . -True

Answer is B.

The generally accepted standard range of audible frequencies is 20 to 20,000 Hz, although the range of frequencies individuals hear is greatly influenced by environmental factors. Frequencies below 20 Hz are generally felt rather than heard, assuming the amplitude of the vibration is great enough. Frequencies above 20,000 Hz can sometimes be sensed by young people. High frequencies are the first to be affected by hearing loss due to age and/or prolonged exposure to very loud noises.
Hence, the statement is false.

Ultrasound is used for removing kidney stones.

Ultrasound is used for removing kidney stones.when ultrasound are targeted on such stone,the stones start vubrating at high frequency.the stone due to this vibratory motion. Breakdown into fine particles.ultrasounds and infrasounds are not audible to man.ultrasound have frequency more than 20kHz.

Infrasound have frequency below 20Hz, X is ultrasound. Y is infrasound, Z is audible sound.

Audible sound has frequency between 20Hz -20,000Hz. 

Human ears can sense sound waves travelling in air whose frequencies $f$ lie in the range of $20Hz$ to $20kHz$

The voices of men, women and children differ from each other
due to the following factors:

i) The pitch is one of the most essential factors to determine the voice of the individual. For example, men have lower-pitched voices while women have higher-pitched voices.

(ii) Second factor which brings in the difference in the voices is the length and the thickness of vocal cords.  from each other due to the following factors

The frequency range of audible sound is $20 Hz$ to $20000 Hz$. Thus, the sound below the frequency 20 Hz is inaudible for human ear and the sound above the frequency 20000 Hz is inaudible for human ear. Thus, the given statement is false.