A) 30 Hz B) 40 Hz C) 80 Hz D) 100 Hz E) 180 Hz The given diagram is the 3rd harmonic at 60 Hz. That means the fundamental is A 20Hz. The other possible standing waves should be multiples of 20 15. An observer hears a sound with frequency 400 Hz. Its wavelength is approximately A) 0.85 m C) 1.2 m C) 2.75 m D) 13.6 m E) 44 m Speed of sound is 340, use v = f A λ 16. As sound travels from steel into air, both its speed and its: A) wavelength increase B) wavelength decrease C) frequency increase D) frequency decrease E) frequency remain unchanged When sound travels into less dense medium, its speed decreases (unlike light) B … however, like all waves when traveling between two mediums, the frequency remains constant. Based on v = f if the speed decreases and the frequency is constant then the must λ, λ decrease also. Questions 17–18: A natural horn (trumpet with no valves) is similar to a pipe open at both ends. A musician plans to create a fundamental frequency of 256 Hz (middle C) using the horn. 17. If sound travels at 350 m/s, what must be the length of this horn? A) 0.34 m B) 0.68 m C) 0.78 m D) 1.36 m E) 1.46 m with n = 1, solve for L B 18. A talented musician can produce a number of overtones on this natural horn. What would be the frequency of the fourth overtone produce when the musician is playing a middle C fundamental? A) 512 Hz B) 768 Hz C) 1024 Hz D) 1280 Hz E) 1536 Hz The fourth overtone is the harmonic, 5 x the fundamental. D 19. One stereo loudspeaker produces a with a wavelength of 0.68 meters while the other speaker produces sound with a wavelength of 0.65 m. What would be the resulting beat frequency? A) 3 Hz B) 23 Hz C) 66.5 Hz D) 500 Hz E) 11333 Hz Determine each separate frequency using the speed of sound as 340 and v = f B λ. Then subtract the two frequencies to get the beat frequency.
A) 30 Hz B) 40 Hz C) 80 Hz D) 100 Hz E) 180 Hz The given diagram is the 3rd harmonic at 60 Hz. That means the fundamental is 20Hz. The other possible standing waves should be multiples of 20 A 15. An observer hears a sound with frequency 400 Hz. Its wavelength is approximately A) 0.85 m C) 1.2 m C) 2.75 m D) 13.6 m E) 44 m Speed of sound is 340, use v = f λ A 16. As sound travels from steel into air, both its speed and its: A) wavelength increase B) wavelength decrease C) frequency increase D) frequency decrease E) frequency remain unchanged When sound travels into less dense medium, its speed decreases (unlike light) … however, like all waves when traveling between two mediums, the frequency remains constant. Based on v = f λ, if the speed decreases and the frequency is constant then the λ must decrease also. B Questions 17–18: A natural horn (trumpet with no valves) is similar to a pipe open at both ends. A musician plans to create a fundamental frequency of 256 Hz (middle C) using the horn. 17. If sound travels at 350 m/s, what must be the length of this horn? A) 0.34 m B) 0.68 m C) 0.78 m D) 1.36 m E) 1.46 m with n = 1, solve for L B 18. A talented musician can produce a number of overtones on this natural horn. What would be the frequency of the fourth overtone produce when the musician is playing a middle C fundamental? A) 512 Hz B) 768 Hz C) 1024 Hz D) 1280 Hz E) 1536 Hz The fourth overtone is the harmonic, 5 x the fundamental. D 19. One stereo loudspeaker produces a with a wavelength of 0.68 meters while the other speaker produces sound with a wavelength of 0.65 m. What would be the resulting beat frequency? A) 3 Hz B) 23 Hz C) 66.5 Hz D) 500 Hz E) 11333 Hz Determine each separate frequency using the speed of sound as 340 and v = f λ. Then subtract the two frequencies to get the beat frequency. B
SHM_%20Wave_%20Sound%20Practice%20Key.docx