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प्रश्न
In following figure shows A, B, C and D are four pendulums suspended from the same elastic string XY. Lengths of pendulum A and D are equal, while the length of pendulum B is smaller and the pendulum C is longer. The pendulum A is set into vibration.
(a) what is your observation? (b) Give reason for your observation.
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उत्तर
(a) Set the pendulum A into vibration by displacing it to one side, normal to its length. It is observed that pendulum D also starts vibrating initially with a small amplitude and ultimately it acquires the same amplitude as the pendulum A initially had. When the amplitude of the pendulum D becomes maximum, the amplitude of the pendulum A becomes minimum since the total energy is constant. After some time the amplitude of the pendulum D will decreases and amplitude of A increases. The exchange of energy takes place only between the pendulums A and D because their natural frequencies are same. The pendulums B and C also vibrate, but with very small amplitudes.
(b) The vibrations produced in pendulum A are communicated as forced vibrations to the other pendulums B, C and D through XY. The pendulums B and C remain in the state of forced vibrations, while the pendulum D comes in the state of resonance.
संबंधित प्रश्न
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?
Resonance is a special case of ______ vibrations, when frequency of the driving force is ______ natural frequency of the body.
Why are the stringed instruments like guitar provided with a hollow sound box?
Differentiate between the following:
Light and sound waves.
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?
When acoustic resonance takes place, a loud sound is heard. Why does this happen? Explain.
The rearview mirror of a motorbike starts vibrating violently at some particular speed of the motorbike. What is the name of the phenomenon taking place? Why does the happen?
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.
