Example, when there's a sound of plane, sometimes, we notice that the window is vibrating altogether too! This will create a louder sound at the same frequency.
Principle of resonance is also used in designing musical instrument, we can find some resonance box in a guitar that is used to make louder sound.
Basically, a resonator (mostly for a musical instrument) should have height of n/4 over the vibrating sound to vibrate altogether (creating resonance).
Example when a tuning fork vibrates at 1500 Hz (take the speed of sound in the air as 300 m/s), and you were pouring a 20 cm height of glass with water, you will hear a resonance at 5 cm height of water. Why? When a source of sound vibrate at 1500 Hz and the speed of sound is 300m/s, it means the wavelength of the sound wave created is 20 cm. To create a resonance to the glass which is filled with water, it should be n/4 over 20 cm, if n=1 it means 1/4 over 20 cm which will result 5 cm.
However if you keep on pouring the water you will hear another resonance at 10 cm (2/4 over 20 cm) and at 15 cm (3/4 over 20 cm) and the last one at 20 cm (4/4 over 20 cm).
Try below work examples :
- A student is vibrating a tuning fork at 340 Hz and the speed of sound is noted as 340 m/s. This tuning fork is going to resonate to water filled measuring cylinder 1 m height. How many times will the louder sound heard when he pours water inside the cylinder? (Answer : 4 times)
- How high should an air pipe to be made to create a resonance to a source of sound that vibrates at 300 Hz and the speed of sound is 300 m/s? (Answer : 25 cm)
- Andy is filling a glass of water at 10 cm and try to find a resonance with a tone. If the speed of sound 300 m/s, what is the frequency of the tone should be transmitted? (750 Hz)
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