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CBSE class 8 sound Extra Questions




This page contains CBSE class 8 sound Extra Questions  along with their answers. We also have notes for this chapter that can be accessed through links given below
Sound notes

Very Short answer type questions

Question 1
Short answer type questions:
(i)What is rarefaction?
(ii)Write two uses of echo.
(iii)Name any three wind instruments.
(iv)How do percussion or membrane instruments produce sound?
(v)What is music?

Answer

(i)It is the opposite compression that reduces the density.
(ii)Two uses of echo are: -
(a)It is used to measure the depth of seas or oceans.
(b)It is used to search submarines and shipwrecks.
(iii)Flute, trumpet and saxophone.
(iv)Percussion or membrane instruments produce sound due to the vibrations occur by stretching the membrane.
(v)A melodious sound that produces a pleasing sensation is called music.


Short answer type questions/HOTS:

Question 2
Vivek has an unpleasant voice whenever he tries to sing in front of his family members and they try to stop him. Why his family members try to stop him?

Answer

Vivek has an unpleasant voice therefore, whenever he sings the sound produced from his larynx makes everyone annoying. This unpleasant sound that irritates everyone is called noise.


Question 3
What is noise population? Give examples of it.

Answer

Continuous producing of unpleasant sound that disturbs the environment is called noise population. Sounds of train, jet airways and drilling are examples of noise population.


Question 4
How do we control noise population?

Answer

We can control noise population in the following ways: -
(i)Avoid playing loud speakers in full volume.
(ii)Industrial regions should be established far away from the residential areas.
(iii)Maintaining silence at necessary places like hospitals, schools and residential areas.


Question 5
Distinguish between audible and inaudible frequencies.

Answer

Audible frequencies are the range of frequency between 20 to 20000 Hz whereas inaudible frequencies are infrasonic and ultrasonic sounds.


Question 6
Calculate the frequency if the time period is 0.2 minutes.

Answer

Given:
T= 0.2 minutes or 12 seconds
T= 1/f
f= 1/T
Therefore f= 1/12 Hz
f= 0.083 Hz


Question 7
Calculate the time period if frequency is 100 Hz.

Answer

Given:
f= 100 Hz or s-1
T= 1/f
T= 1/100 seconds
T= 0.01 seconds


Question 8
When we pluck the strings of a guitar, thicker strings produce low pitch while thinner strings produce high pitch. Why?

Answer

Thick strings of a guitar produce a low pitch while thinner strings produce a high pitch because thinner strings vibrate faster than thicker strings.


Question 9
How do wind instruments produce sound?

Answer

Wind instruments produce sound because of the vibration occurs in their air column.


Long answer type questions:

Question 10
Explain the parts of human ear. Draw a well-labelled diagram of human ear.

Answer

Human ears are the organs that enable us to hear sound. It consists of three parts: -
Outer ear: This part of ear is visible to us. It is divided into three parts: pinna, eardrum and ear canal. The pinna collects the sound waves and transfer them to the ear canal that has eardrum located at its end where these waves strike.
Middle ear: At this location, three parts are present- hammer, anvil and stirrup. The vibrations that pass through the eardrum move to these three tiny bones. Afterwards, they transfer the vibrations to the inner ear.
Inner ear: This part of ear has a long coiled-like tube called cochlea that is filled with fluid and contains many hair cells, which are highly sensitive. The vibrations move to the fluid then carried by hair cells to the brain with the help of auditory nerves. Later, the brain receives these vibrations and tries to access the memory to understand the sound.
class 8 sound Extra Questions for CBSE


Question 11
Explain the human voice box. Draw a well-labelled diagram.

Answer

The voice box of human beings is known as larynx. The location of the larynx in the body is the upper end of the windpipe or trachea. There are two thin membranous structures called vocal cords responsible for controlling the production of sound. They have a narrow slit where air is blown in and out. This air collides and passes through the slit vibrates and produces sound. Moreover, different pitches depend upon the thickness of the vocal cords.
CBSE class 8 sound Extra Questions


Summary

This CBSE class 8 sound Extra Questions is prepared keeping in mind the latest syllabus of CBSE . This has been designed in a way to improve the academic performance of the students. If you find mistakes , please do provide the feedback on the mail.


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