Class 9 Science - Chapter Sound NCERT Solutions | Explain how the human ear works.
Explain how the human ear works.
Different sounds produced in our surroundings are collected by pinna. The collected sound passes through the auditory canal. At the end of the auditory canal, there is a thin membrane called the eardrum or tympanic membrane. When compression the medium reaches the eardrum the pressure on the outside of the membrane increases and force the eardrum inward. Similarly, the eardrum moves outward when the rarefaction reaches it. The eardrum starts vibrating back and forth rapidly when the sound waves fall on it. The vibrating eardrum sets the small bone hammer into vibration. The vibrations are passed from the hammer to the second bone anvil, and finally to the third bone stirrup. The vibrating stirrup strikes on the membrane of the oval window and passes its vibration to the liquid in the cochlea. This produces electrical impulses in nerve cells. The auditory nerve carries these electrical impulses to the brain. These electrical impulses are interpreted by the brain as sound and we get a sensation of hearing.
More Questions From Class 9 Science - Chapter Sound
- Q:-
Explain the working and application of a sonar.
- Q:-
Explain how sound is produced by your school bell.
- Q:-
Explain how defects in a metal block can be detected using ultrasound.
- Q:-
Distinguish between loudness and intensity of sound.
- Q:-
A sound wave travels at a speed of 339 m s-1. If its wavelength is 1.5 cm, what is the frequency of the wave? Will it be audible?
- Q:-
Which characteristic of the sound helps you to identify your friend by his voice while sitting with others in a dark room?
- Q:-
A sonar device on a submarine sends out a signal and receives an echo 5 s later. Calculate the speed of sound in water if the distance of the object from the submarine is 3625 m.
- Q:-
Which wave property determines
(a) loudness, (b) pitch? - Q:-
How is ultrasound used for cleaning?
- Q:-
Suppose you and your friend are on the moon. Will you be able to hear any sound produced by your friend?
Popular Questions of Class 9 Science
- Q:-
Which of the following has more inertia: (a) a rubber ball and a stone of the same size? (b) a bicycle and a train? (c) a five-rupees coin and a one-rupee coin?
- Q:-
State the universal law of gravitation.
- Q:-
Which of the following are matter?
Chair, air, love, smell, hate, almonds, thought, cold, cold-drink, smell of perfume.
- Q:-
A force of 7 N acts on an object. The displacement is, say 8 m, in the direction of the force (Fig. 11.3). Let us take it that the force acts on the object through the displacement. What is the work done in this case?
- Q:-
What is meant by a pure substance?
- Q:-
In a reaction, 5.3 g of sodium carbonate reacted with 6 g of ethanoic acid. The products were 2.2 g of carbon dioxide, 0.9 g water and 8.2 g of sodium observations are in agreement with the law of conservation of mass.
sodium carbonate + ethanoic acid → sodium ethanoate + carbon dioxide + water
- Q:-
What are canal rays?
- Q:-
State any two conditions essential for good health.
- Q:-
How is our atmosphere different from the atmospheres on Venus and Mars?
- Q:-
Who discovered cells, and how?
Recently Viewed Questions of Class 9 Science
- Q:-
What is the greenhouse effect?
- Q:-
What is the acceleration of free fall?
- Q:-
A motorboat starting from rest on a lake accelerates in a straight line at a constant rate of 3.0 m s-2 for 8.0 s. How far does the boat travel during this time?
- Q:-
State the universal law of gravitation.
- Q:-
In the hierarchy of classification, which grouping will have the smallest number of organisms with a maximum of characteristics in common and which will have the largest number of organisms?
- Q:-
How are clouds formed?
- Q:-
Why are we normally advised to take bland and nourishing food when we are sick?
- Q:-
What precautions can you take in your school to reduce the incidence of infectious diseases?
- Q:-
An object thrown at a certain angle to the ground moves in a curved path and falls back to the ground. The initial and the final points of the path of the object lie on the same horizontal line. What is the work done by the force of gravity on the object?
- Q:-
Name the technique to separate
(i) butter from curd,
(ii) salt from sea-water,
(iii) camphor from salt.
- All Chapters Of Class 9 Science
- All Subjects Of Class 9