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Questions
Differentiate between the forced and resonant vibrations.
State two differences between forced and resonant vibrations.
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Solution
| Forced Vibrations | Resonant vibrations |
| These are vibrations of a body under an external periodic force of frequency different than the body's natural frequency. | These are vibrations of a body under an external periodic force of frequency exactly equal to the natural frequency of the body. |
| The amplitude of the vibration is usually small. | The amplitude of vibration is very large. |
| The body's vibrations are not in phase with the external periodic force. | The vibrations of the body are in phase with the external periodic force. |
| These vibrations last very short after the periodic force has ceased to act. | These vibrations last long after the periodic force has ceased to act. |
Notes
Students should refer to the answer according to their questions.
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RELATED QUESTIONS
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.
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3) Why does the paper rider fly off when the stem of tuning fork B is touched to the box?
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- State the principle illustrated by this experiment.
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(ii) Which characteristic of sound, makes it possible to recognize a person by his voice without seeing him?
On keeping the stem of a vibrating tuning fork on the surface of a table, a loud sound is heard. Give reason.
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