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प्रश्न
उत्तर
Bats make a series of twittering sound, so high pitched that human ear can not hear. These sound waves strike against the obstacles less in their path of flight and send back echoes to the bat’s ear. The echoes tell the bats, how they must turn in the air to avoid colliding with the obstacles or with one another.
संबंधित प्रश्न
Which characteristics of the sound helps you to identify your friend by his voice while sitting with others in a dark room?
Write true or false for a given statement.
Loudness depends on frequency.
Write the audible range of frequency for the normal human ear.
At 20°C, the minimum distance of a person from a sound reflecting surface to hear an echo is :
What is a transverse wave? In which medium: solid, liquid or gas, can it be produced?
The speed of light in air is :
Select the correct option:
In case of longitudinal waves, the particles of the medium vibrate:
A continuous progressive transverse wave of frequency 8 Hz moves across the surface of a ripple tank
If the wavelength of the transverse wave is 32 mm, calculate the speed with which wave travels across the surface of the water.
State the effect of pressure on the speed of sound in air.
The time interval between a lighting flash and the first sound of thunder was found to be 6 s. If the speed of sound in air is 330 ms-1, find the distance of the flash from the observer.
Match the following.
| Ultrasonics | Frequency below 20Hz |
| Speed of sound in air | Needs material medium |
| Infrasonics | 330ms-1 |
| Sound propagation | Frequency more than 20000 Hz |
Vibration of object produces ______.
Name two musical instruments which produce sound by vibrating strings.
Longitudinal waves are produced in solids liquids and also in gases.
What happens to the speed of sound when it gases from a solid to a gaseous state?
______ is an unwanted sound.
What is a wave?
