15. 1600 m/s 400 m/s 340 m/s Speed In body tissue 3.5 MHz Ultra sound 0.8m Radio from space In water 45mm 30 kHz sonar 8Hz Water ripples In vacuum 6GHz Microwave In air 0.1nm X-rays water 0.61 um 3.6 E14 Hz Yellow light In air 2000 Hz Sound Medium Wavelength Frequency Wave
24. Fundamental frequency. l = /2 1 st overtone. l = 2 nd overtone. l = 3/2 (1.5 ) 3 rd overtone. l = 2 4 th overtone. l = 5/2 (2.5 ) 5 th overtone. l = 3 6 th overtone. l = 7/2 (3.5 ) node node Anti-node n n n a a
25.
26. Experiment Sig Gen Vibrator String of known length l 50 Hz Use the sig gen to set up the standing wave with the natural frequency of the string. Use the wave formula to predict the frequency of the next 4 standing waves. Test your hypothesis c 5 c 4 c 3 c 2 c 1 5 4 3 2 1 f 5 f 4 f 3 f 2 f 1
27. In a pipe with one enclosed end the natural (fundamental) frequency sets up a standing wave with a wavelength of /4 the overtones then go up in steps on /2
28. For a pipe with an enclosed end to resonate the standing must have a node at the closed end and an anti-node at the open end. The first situation when this arises is when the wave created by the fundamental frequency has a wave length 4 times greater than the length of the pipe. L= /4 or = 4L Each further fundamental needs an extra half wave in the pipe to satisfy the conditions so the next fundamental will have a wave length of = 4/3 L or a length of L= 3/4
29. In a pipe with open ends the natural (fundamental) frequency sets up a standing wave with a wavelength of /2 the overtones then go up in steps on /2
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