Tag: audible, infra and ultra sound with its application

Questions Related to audible, infra and ultra sound with its application

Which of the following sounds are not audible?

audible, infra and ultra sound with its application study of sound physics

  1. a tuning fork vibrating 400 times in 2 sec.

  2. a tuning fork vibrating 3600 times in 60 s.

  3. tuning fork vibrating 1 time in 1 sec

  4. tuning fork vibrating 900 times in 2 sec

Show answer
Correct Option: C
Explanation:

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.

Why we can hear the sound produced by bees but we cant hear the sound of vibrations of pendulum?

audible, infra and ultra sound with its application study of sound physics

  1. Sound of vibrations of pendulum is in audible rays

  2. Sound of bees are in audible range

  3. Sound of bees are in infrasonic range while sound of vibrations of pendulum are in ultrasonic range

  4. None is true

Show answer
Correct Option: B
Explanation:

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

A vibrating body produces sound. However no sound is heard when a simple pendulum oscillates in air. Why?

audible, infra and ultra sound with its application study of sound physics

  1. Frequency of vibration of pendulum is very high.

  2. Frequency of vibration of pendulum is more than 20 Hz

  3. Frequency of vibration of pendulum is less than 20 Hz

  4. Frequency of vibration of pendulum is exactly equal to 20 Hz.

Show answer
Correct Option: C
Explanation:

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.

Range of frequency of ultrasound is:

audible, infra and ultra sound with its application study of sound physics

  1. 2 kHz - 106 Hz

  2. 25 kHz - 1015 Hz

  3. 2 kHz - 1010 Hz

  4. 20 kHz - 107 Hz

Show answer
Correct Option: D
Explanation:

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.

What are the uses of ultrasonic sounds?

audible, infra and ultra sound with its application study of sound physics

  1. To track medical problems

  2. To study molecular structures

  3. For navigational studies and by animals to locate prey and obstacles

  4. All of the above

Show answer
Correct Option: D
Explanation:

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.

If a vibration is produced 200 times per second.

audible, infra and ultra sound with its application study of sound physics

  1. It will be audible by the human ear

  2. It would not be audible by the human ear.

  3. It depends on its amplitude.

  4. All

Show answer
Correct Option: A
Explanation:

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.

Which of the following animals can hear ultrasounds?
a) Dogs, b) Whales, c) Bats, d) Dolphins

audible, infra and ultra sound with its application study of sound physics

  1. a and c

  2. b, c and d

  3. a, b and d

  4. All of these

Show answer
Correct Option: D
Explanation:

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.

It has been seen that the behaviour of animals becomes unusual just before the tremor is felt. What is the reason behind this?

audible, infra and ultra sound with its application study of sound physics

  1. because animals are able to detect infrasonic waves produced at the time of tremor.

  2. because animals are able to detect ultrasonic waves produced at the time of tremor.

  3. because animals are able to detect audible waves produced at the time of tremor.

  4. all

Show answer
Correct Option: A
Explanation:

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.

How the bats can locate their prey?

audible, infra and ultra sound with its application study of sound physics

  1. The ultrasonic waves produced by a bat spread out.

  2. The ultrasonic waves after reflection from a prey reach the bat.

  3. both

  4. none

Show answer
Correct Option: C
Explanation:

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.

Which of the following frequency of sound can be heard by a dog but not by a man?

audible, infra and ultra sound with its application study of sound physics

  1. 50,000 hertz

  2. 15,000 hertz

  3. 1200 hertz

  4. none

Show answer
Correct Option: A
Explanation:

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.