Sound – Science – (NCERT Solutions for Class 9)
Page – 163
- Explain how sound is produced by your school bell.
- Why are sound waves called mechanical waves?
- Suppose you and your friend are on the moon. Will you be able to hear any sound produced by your friend?
Page – 165
- Which wave property determines (a) loudness, (b) pitch?
- Guess which sound has a higher pitch: guitar or car horn?
- What are wavelength, frequency, time period and amplitude of a sound wave?
- How are the wavelength and frequency of a sound wave related to its speed?
- Calculate the wavelength of a sound wave whose frequency is 220 Hz and speed is 440 m/s in a given medium.
- A person is listening to a tone of 500 Hz sitting at a distance of 450 m from the source of the sound. What is the time interval between successive compressions from the source?
- Distinguish between loudness and intensity of sound.
Page – 167
- In which of the three media; air, water or iron does the sound travel the fastest at a particular temperature?
- An echo returned in 3 s. What is the distance of the reflecting surface from the source, given that the speed of sound is 342 m /s?
- Why are the ceilings of concert halls curved?
- What is the audible range of the average human ear?
- What is the range of frequencies associated with
- A submarine emits a SONAR pulse, which returns from an underwater cliff in 1.02 s. If the speed of sound in salt water is 1531 m/s, how far away is the cliff ?