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प्रश्न
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उत्तर
Sounds can be roughly divided into two categories: (i) music, and (ii) noise.
Regularity, contrivity and rapidity make musical sounds different from a noise. The distinction between music and noise is not very sharp; it is subjective.
| Music | Noise |
| 1. It is pleasant, smooth and agreeable to the ear. | 1. It is harsh, discordant and displeasing to the ear. |
| 2. It is produced by the vibrations which are periodic. | 2. It is produced by an irregular succession of disturbances. |
| 3. All the component waves are similar without any sudden change in their wavelength and amplitude | 3. The component wave chanqes their character suddenly and they are of short duration.. |
| 4. The sound level is low (below 30 dB). | 4. The sound level is hiah (above 120 dB). |
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संबंधित प्रश्न
How does the medium affect the amplitude of free/natural vibrations of a body?
In following figure shows A, B , C and D represent test tube each of height 20 cm which are filled with water up to heights of 12 cm, 14 cm, 16cm and 18cm respectively. If a vibrating tuning fork is placed over the mouth if test tube D, a loud sound is heard.
- Describe the observations with the tubes A, B and C when the vibrating tuning fork is placed over the mouth of these tubes.
- Give the reason for your observation in each case.
- State the principle illustrated by the above experiment.
In fig. , P, Q, R and S represent test tubes each of height 20 cm which are filled with water upto heights of 10 cm, 14 cm, 16 cm and 18 cm respectively. If a vibrating tuning fork is placed over the mouth of test tube Q, a loud sound is heard.
(i) Describe the observations with the tubes P, R and S.
(ii) Give the reason for your observation in each case.
(iii) State the principle illustrated by the above experiment.
In fig. shows two tuning forks P and Q of the same frequency mounted on separate sound boxes with their open ends facing each other. The fork A is set into vibration. (i) Describe your observation. (ii) State the principle illustrated by this experiment.
Differentiate between the following:
Free and forced vibrations.
Explain why stringed musical instruments, like the guitar, are provided with a hollow box.
The rearview mirror of a motorbike starts vibrating violently at some particular speed of the motorbike, what could be done to stop the violent vibrations.
Explain why are soldiers asked to walk out of step while crossing bridges?
When a tuning fork, struck by a rubber pad, is held over a length of the air column in a tube, it produces a loud sound for a fixed length of the air column. Name the above phenomenon. How does the frequency of the loud sound compare with that of the tuning fork? State the unit for measuring loudness.
Explain a person walking past a railway line, in the middle of night hears a ringing sound along with the sound of his footsteps.
