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प्रश्न
What do you understand by forced vibrations?
उत्तर
Sometimes to keep a body vibrating, a periodic force is applied to it. In such a case, the body does not vibrate with its own natural frequency but gradually starts vibrating with the frequency of the applied periodic force. Such vibrations produced in a body are called forced vibrations, e.g., in a string of musical instruments, when the vibrations producing a loud sound.
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संबंधित प्रश्न
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?
What are forced vibrations?
Resonance is a special case of ______ vibrations, when frequency of the driving force is ______ natural frequency of the body.
A vibrating tuning fork, held over an air column of a given length with its one end closed, produces a loud audible sound. Name the phenomenon responsible for it and explain the observation.
Why are the stringed instruments like guitar provided with a hollow sound box?
Two pendulums C and D are suspended from a wire as shown in the figure give below. Pendulum C is made to oscullate by displaying it from its mean position. It is seen that D also starts oscillating.
(i) Name the type of oscillation, C will execute.
(ii) Name the type of oscillation, D will execute.
(iii) If the length of D is made equal to C then what difference will you notice in the oscillations of D ?
(iv) What is the name of the phenomenon when the length of D is made equal to C ?
When acoustic resonance takes place, a loud sound is heard. Why does this happen? Explain.
State two ways in which resonance differs from forced vibrations.
When the stem of vibrating tuning fork is pressed on a table, the tabletop starts vibrating. These vibrations are definitely an example of ______.
