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प्रश्न
Differentiate between the following:
Free and forced vibrations.
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उत्तर
| Free vibrations | Farced vibrations |
| 1. When a body vibrates with its natural frequency and ti me period which is characteristic of the body itself, it is said to have free vibrations. | 1. When a body is set into vibrations with the help of a strong periodic force then the vibration is said to be forced vibration. The frequency of such vibrations may not be equal to the natural frequency of the body. |
| 2. It is difficult to realize such vibrations in practice. They can take place only in vacuum. | 2. Such vibrations can be realized in practice. |
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संबंधित प्रश्न
Define the Resonance phenomenon?
The adjacent diagram shows three different modes of vibrations P, Q and R of the same string.
(i) Which vibration will produce a louder sound and why?
(ii) The sound of which string will have maximum shrillness?
(iii) State the ratio of wavelengths of P and R.
The diagram above shows a wire stretched over a sonometer. Stems of two vibrating tuning forks A and Bare touched to the wooden box of the sonometer. It is observed that the paper rider (a small piece of paper folded at the centre) present on the wire flies off when the stem of vibrating tuning fork B is touched to the wooden box but the paper just vibrates when the stem of vibrating tuning fork A is touched to the wooden box.
1) Name the phenomenon when the paper rider just vibrates.
2) Name the phenomenon when the paper rider flies off.
3) Why does the paper rider fly off when the stem of tuning fork B is touched to the box?
Describe a simple experiment to illustrate the phenomenon of resonance and explain it.
In following figure shows two tuning forks A and B of the same frequency mounted on two separate sound boxes with their open ends facing each other. The fork A is set into vibration.
- Describe your observation.
- State the principle illustrated by this experiment.
(i) Define resonant vibrations.
(ii) Which characteristic of sound, makes it possible to recognize a person by his voice without seeing him?
A bucket kept under a running tap is getting filled with water. A person sitting at a distance is able to get an idea when the bucket is about to be filled.
(i) What change takes place in the sound to give this idea?
(ii) What causes the change in the sound?
Explain why does the rear mirror of a motorbike start Vibrating Violently, at some particular speed of motorbike?
What do you understand by forced vibrations?
