Mention the property of vibrations which determine the pitch of the sound. Briefly explain along with some examples.

5

(a)

How is sound produced and how is it transmitted and heard by us?

5

(a)

Explain in detail how sound travel slower than light.

5

(a)

An alarm bell is kept inside a vessel as shown in figure. A person standing close to it can distinctly hear the sound of alarm. Now, if the air inside the vessel is removed completely, how will the loudness of alarm get affected for the same person?

5

(a)

Explain in brief about eardrum. Also explain how does it play an important role in hearing.

5

(a)

The town hall building is situated close to Boojho's house. There is a clock on the top of the town hall building which rings the bell every hour. Boojho has noticed that the sound of the clock appears to be much cleared at night. Explain

5

(a)

Anjali's grandfather was talking to her about the quality of sound produced by different musical instruments. The instruments like sitar, harmonium, flute, etc., give us a pleasant sensation of hearing. The dholak on the other side creates a noise.
(a) Mention the name of the vibrating part of sitar.
(b) Briefly explain how the loudness is created by dholak.
(c) We hear a shrilling sound by flute. Explain why?
(d) Mention the values displayed by Anjali's grandfather

5

(a)

Sketch larynx and explain its function in your own words

5

(a)

How can noise pollution be controlled?

5

(a)

Presence of excessive or unwanted sounds in the environment is called noise pollution. List some sources of noise pollution. What are the harms of noise pollution. What are the measures to control noise pollution?

5

(a)