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Question
How do you tune your radio set to a particular station ? Name the phenomenon involved in doing so and define it.
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Solution
Resonance is the basis for radio tuning. You may alter the frequency of the electrical vibrations produced by them by adjusting the values of the individual components in the electronic circuits that make them up. Changing the values of a few electrical components causes vibrations at a frequency that matches the desired radio wave frequency, and that's all. When the two frequencies are in resonance with one another, the incoming waves carry the signal energy of the matching frequency. In the receiver set, the signal is then amplified.
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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.
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?
How does the medium affect the amplitude of free/natural vibrations of a body?
Resonance is a special case of ______ vibrations, when frequency of the driving force is ______ natural frequency of the body.
Name the phenomenon involved in tuning your radio set to a particular station and define it.
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.
In Fig. A, B, C and D are four pendulums suspended from the same elastic string XY. The lengths of pendulum A and D are equal, while the length of pendulum B is shorter and of the pendulum C is longer. Pendulum A is set into vibrations.
- What is your observation about the vibrations of pendulum D?
- Give reason for your observation in part (a).
- What type of vibrations take place in pendulums Band C?
- Give reason for the answer in part (c).
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?
What do you mean by resonance? When does resonance occur?
A string stretched between its ends is made to vibrate by placing the stem of a vibrating tuning fork at its one end. State three ways how you will increase the frequency of note produced by the string.
