# NCERT Class-9 Science Solutions: Chapter 12-Sound Part 2 (For CBSE, ICSE, IAS, NET, NRA 2023)

Get top class preparation for CBSE/Class-9 right from your home: get questions, notes, tests, video lectures and more- for all subjects of CBSE/Class-9.

Question 8:

Infrasound can be heard by

1. Dog
2. Bat
3. Rhinoceros
4. Human beings

Question 9:

Before playing the orchestra in a musical concert, a satirist tries to adjust the tension and pluck the string suitably. By doing so, he is adjusting

1. Intensity of sound only
2. Amplitude of sound only
3. Frequency of the sitar string with the frequency of other musical instruments
4. Loudness of sound

Question 10:

The given graph (Figure) shows the displacement versus time relation for a disturbance travelling with velocity of . Calculate the wavelength of the disturbance.

From the graph

Time period,

Frequency,

Wavelength,

Where,

Question 11:

Which of the above two graphs (a) and (b) (Figure) representing the human voice is likely to be the male voice? Give reason for your answer.

Graph (a) represents the male voice. Usually the male voice has less pitch (or frequency) as compared to female. Male voice have generally lower pitch and hence lower frequency of sound. From the graph, wave “a” is likely to be of a male voice

Question 12:

A girl is sitting in the middle of a park of dimension . On the left side of it there is a building adjoining the park and on right side of the park, there is a road adjoining the park. A sound is produced on the road by a cracker. Is it possible for the girl to hear the echo of this sound? Explain your answer.