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प्रश्न
What is a soundboard ? Explain the working of a soundboard with the help of a labelled diagram.
उत्तर
A soundboard is a concave board that is placed behind the speaker in large halls or auditoriums so that the speech can be easily heard even by the person sitting at a considerable distance. The soundboard works in the following manner as the speaker is placed at the focus of the concave board. The concave surface of the soundboard reflects the sound of the speaker toward the audience and hence prevents the spreading of sound in various directions. Due to this, sound is distributed uniformly throughout the hall and even the persons sitting at the back of the hall can hear the speech easily.
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संबंधित प्रश्न
The human ear can detect continuous sounds in the frequency range from 20 Hz to 20,000 Hz. Assuming that the speed of sound in air is 330 ms1 for all frequencies; calculate the wavelengths corresponding to the given extreme frequencies of the audible range
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The following diagram shows three ways in which the string of an instrument can vibrate.
(a) which of the diagram shows the principal note?
(b) which has the frequency four times that of the first?
(c) what is the ratio of the frequency of the vibration in (i) and (ii)?
Write the approximate value of the speed of sound in air.
Why is an echo not heard when the distance between the source of sound and reflection body is less than 10 m?
Waves produced on the surface of the water are formed to move with a velocity of 24 ms−1. If the wavelength of these waves equals 20 cm. find the
(i) frequency (no. of waves produced per second)
(ii) the time period (i.e. the time required to produce one wave) for these waves.
Match the following:
| 1. | Stethoscope | a. | Repeated reflections |
| 2. | Echogram | b. | Multiple reflections |
| 3. | SONAR | c. | Ultrasonic waves |
| 4. | Reverberation | d. | Speed of underwater objects |
