Question

A sound wave a frequency of 20 kHz emerges through a circular opening that has a diameter of 0.78 m. Concepts: The diffraction angle for a wave emerging through a circular opening is given by sin(theta) = 1.22 /D, where is the wavelength of the sound and D is the diameter of the opening. What is meant by the diffraction angle? the angle that the sound wave bends away from the center before passing through the opening the location of the first maximum intensity point on either side of the center the angle that the sound wave bends toward the center before passing through the opening the location of the first minimum intensity point on either side of the center How is the wavelength related to the frequency of the sound? (Use the following as necessary: f and v. Do not substitute numerical values; use variables only.) Is the wavelength of the sound in air greater than, smaller than , or equal to the wavelength in water? (Note: The speed of sound in air is 343 m/s and the speed of sound in water is 1482 m/s.) greater than smaller than equal to why? (select all that apply.) The sound's frequency is independent of the medium. The speed of sound is lower in air than in water. The speed of sound is lower in air than in water. The sound's frequency depends on the medium. Is the diffraction angle of the sound in air greater than, smaller than, or equal to the diffraction angle in water? greater than smaller than equal to explain. The diffraction angle is proportional to the wavelength, and the wavelength of sound is smaller in air than in water. The diffraction angle is inversely proportional to the wavelength, and the wavelength of sound is smaller in water than in air. The diffraction angle is proportional to the wavelength, and the wavelength of sound is smaller in water than in air. The diffraction angle is inversely proportional to the wavelength, and the wavelength of sound is smaller in air than in water. Calculations: Find the diffraction angle theta when the sound travels in air. Find the diffraction angle theta when the sound travels in water.

Answer 1

1 a) The angle that the sound waves bends away from the centre before passing through the opening b)L-speed/frequency L-v/f c) the speed of sound in water is much greater than the speed of sound in air. Since wavelength is directly proportional to speed so Wavelength of sound in water is much greater than the wavelength of sound in air. So in this case answer is b smaller than d) answer is c since the speed of sound is lower in air than water e) answer is the diffraction angle is proportional to wavelength and the wavelength of sound is smaller in air than in water