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习题练习：Physics Unit12: Sound
本习题练习试卷来源于51fly国际课程 (https://51fly.win)， 为试卷打印版，您也可以在网站平台(https://autodiscover.51fly.win/)直接 访问本试卷的在线电子版并查看正确答案与解析，搜藏保存任意题目到收藏集。 访问方法: 平台首页左上角"通过试卷号快速访问"输入试卷号 70，并点击直达试卷；或浏览器地址栏内直接输入本试卷链接 https://autodiscover.51fly.win/test70.html  教师使用本平台可以抽题组卷或一键复制他人试卷，布置为在线考试或在线作业，全自动判分成绩一键排序导出，省时省力。
 作者: physics  发布日期: 2022-09-26 09:56    总分: 87分  得分: _____________

答题人: 游客未登录  开始时间: 22年08月07日 09:59  切换到: 整卷模式

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1#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Which of the followingvy9m-v f+l 2hy is a false statement?

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2#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  In general, sound is conducted d g)umhl 54g9n/qfc6s fastest through

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3#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What is the speed of sound in a steeo2yx-dw v u*wo)up921eqh/jbl rod?

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4#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  As the temperature of the air icqkoh7uvu1y k *(n+.bncreases, what happens to the velocity of sound? (Assume that all ot 7v(c bqk1ho+unk.u* yher factors remain constant.)

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5#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Compared to the velocity of a 400 Hz sound, the velocity of a 200 Hz soun,30q3u kmmta ud through aa,m0u33 u qmktir is

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6#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Compared to the wavelength of a 400 Hz sound, the wavelength of a 200 Hz soucha,ca6k8+s n nd in 6aa chks,+c8nair is

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7#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Sound vibrations with frequv *+)djjsut q ,+ d7pvw0g9nkhencies greater than 20,000 Hz are called

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8#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Sound vibrations with frequency less than 20 Hz are calledd yfd;4vg:gfc) d7im/

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9#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Suppose that a sound sourceii /; msycfo1lp .nf5 ,9k;*ng8avpzs is emitting waves uniformly in all directions. If you moy sf fin p*.svm85lakc9oz,1 ;;/npgive to a point twice as far away from the source, the frequency of the sound will be

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10#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  For spherically diverging waves, intensity is proportional8tmw n+w 06f6id u*4b7v l *nepa1viau to

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11#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The intensity of a point source fnd .ww 94w5vqkmp*-mat a distance d from the source is I. What is the wf95w4m* pvdkqmw. -nintensity at a distance 2d from the source?

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12#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  You double your distance from a sound source that is ruag5h s (o.v+aadiating equally in all directions. What happens to the intensity of h oasavg+.5( uthe sound? It reduces to

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13#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  You double your distance from a sohwsovy (9i+a ;und source that is radiating equally in all directions. What happens to the intensity;+ ow9v( yshia level of the sound? It drops by

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14#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Which of the following increases as a sound becwkl w.7fot t79abh:r) omes louder?

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15#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  You move slowly toward a speaker emitting a pure tone. What characteristic of gs*w0,qdp8) kzrg1htu sy.e.3(kifu the sound increasedsy) gk1uf*308e pktsw ,qiuhz(.g. r s?

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16#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What determines "loudness" oai 8 .hvlf q p-;s7wk*;lhko7vf a musical note?

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17#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What determines the "pitch" of a musical 7j0* j nasgp0 6mb(lyanote?

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18#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  When sound passes from airkl kzz,k ly5:x.4p1 0mjxw3l c into water

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19#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Pressure and displacement waves) geopu,e ku)qp4s7q f1d*x u./.ekce are

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20#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Consider the standing wave on a guitar stri6 yvx4 zk289dgd9bd-5v vmdzyc :/sqkng and the sound wave generated by the guitar as a result of this vibration. What do these td d-yd9v4:k/ zq bxg 8k9vdvcs 2y5z6mwo waves have in common?

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21#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  In a resonating pipe which is open,xv8jv4q npq* at both ends, there

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22#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Consider an open pipe of length L. What are the*kbi+j ca d rs-e+d)7y wavelengths of the three lowest tones produced byjs e)r+dc + d*a-kyi7b this pipe?

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23#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The lowest tone to resonate in an open pipe of length L is 200 Hz. Whi *s2 bt62e3a+vcljlimwf43czch one of the following frequencies will not relm *e6bslj3 324izc+cfw2vta sonate in the same pipe?

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24#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  An open pipe of length L is r:p6 l(u, vluijnua xys+u dfl)v0 3,f/f l/z5sesonating at its fundamental frequency. Which statement is correvy+5ludj i: pfa/uzsv)l,0f63(,u/lu fx lns ct?

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25#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  In a resonating pipe which is open at one end and closed at the o8pjuv ilohf+rl;6m* 4ther, there

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26#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Consider a closed pipe of length L. Wtkxmeg- ts3,d)2 z, axhat are the wavelengths of the three lowest tones produced by thistx aem t3g,s)kz,2d x- pipe?

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27#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The lowest tone to resonate in a closed pipeu 2cw2 :dmz9 5r(eaicm of length L is 200 Hz. Which of the following frequencies c(e9w2u:ad m m25 rcizwill not resonate in that pipe?

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28#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A pipe of length L ckuj48d1 scl:w losed at one end is resonating at its fundamental frequency. Which state1:4ksc w8juldment is correct?

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本习题练习题目来源于51fly国际课程 (https://51fly.win)，学生可刷题练习，扫右侧二维码或加微信skysky1258，获取更多资料
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29#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A person stands between two speakers drive kx16)u 6z9xd/o vaoukn by the same source. Each speaker produces a tone with a frequency of 200 Hz on a day when the speed of sound is 330 m/s. The oaz udvuk6kx x)916o/person is
1.65 m from one speaker and 4.95 m from the other. What type of interference does the person sense?

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30#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  In order to produce beats, the two sound wavespwbi/o 2l3hc w v19ye. should have

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31#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Two pure tones are sounded together and a particular beat freqc*smbvttq(d63r ikq6/fq kp.a* -z w 7uency is heard. What happens to the beat frequency if the frequency of one of the tones is increasq s/-att bdr6 6qm*ipzcf3 (wv*.7qkked?

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32#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The Doppler shift explainax(o4 dx-1l.jbqe j)ts

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33#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A sound source approaches a stationary observer. The frequency heard by the oby32n llxpmnhl6t1. 7l serx6 n l17lp nlhy2m3tl.ver is

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34#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A sound source departs from a stationary observer. The frequency heard *,yg5ngyazos2 41kw8 wlpa4 uby the obsyak 8 gz p5*gnuwyswa42l 4o,1erver is

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35#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  If a jet plane were to double its MACH-spesn15 h odh:nwg6d2 *q: zx/pzoed, its half-angle will decrease by a facd:zn15np 6 wq2g/*: ood hsxzhtor of:

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36#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The speed of an ultrasonic sound of frequency 45 kHz in air is 352 xr;ju5(rwj* h6sr;r osddm, 6m/s. What is the w jrs5*xrdr 6jh 6u;os(mrd;,air temperature?

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37#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What is the ratio of the4u ,shoeq24 ei speed of sound in air at $0 \; ^{\circ}C$ to the speed at $100 \; ^{\circ}C$?

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38#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  On a day when the speed of sound in air +5oekbcy5*c l )b/xkdis 340 m/s, a bat emits a shriek whose echo reaches it 0.0250 s later. How far away was the object that reflected back the so l yb*+e/ k5)cbd5ckxound?

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39#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  You shout at a cliff, and hear the echo in 4.00 s. The temperavjj1 15-fq amfr /m-dpture is $0 \; ^{\circ}C$. How far away is the cliff?

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40#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  If you hear thunder 5.0 s after seeing a flash of lig5wdiwo3k8x(f cdn;y5 htning, the distance to the lightning strikif85 wnwd 5o;xcy3(dk e is about

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41#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  An echo is heard 2.0 s from a cliff on a day the temperature l +fh 2c:lpr/eis $15 \; ^{\circ}C$. Approximately how far is the cliff from the observer?

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42#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  On a $30 \; ^{\circ}C$ day, there is an explosion. The sound is heard 3.4 s after seeing the flash. How far away was the explosion?

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43#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  You drop a stone into a deep well and hear the+1dzl dsz0um6 splash 2.5 s later. How deep is the well? (Ignore air resistance, and assume the v6smd 1ud+lz0 zelocity of sound is 340 m/s.)

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44#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The wavelength in air of a sound wave b3g r3 bhzdo1:of frequency 500 Hz is

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45#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Sound traveling in air a0o0w;y5 yqesk pv6mk )t $23 \; ^{\circ}C$ enters a cold front where the air temperature is $2 \; ^{\circ}C$. If the sound frequency is 1500 Hz, determine the wavelength in the warmer air and in the colder air.

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46#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What is the intensity level of a sound;l:,xt ar1* .ua1bblutpc(l -gdm8g yj8/ dcy with intensity $10^{-3} \; W/m^{2}$?

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47#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What is the intensity okmlyi1qe b1q8x7wn 5-f a 70-dB sound?

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48#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What is the ratio of the intensities ofxj.giv/8qarjx 0z38 q two sounds with intensity levels of 70 dB and 40 dB3 r axj/08i.xjqv8qz g?

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49#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The intensity level by 15 engines in a garage is 100 dB. Whdk -o d85bm1d,/fo4dc (zzfj6)knaeb at is the intensity level nf 6c4(8mzb) o 15kd,dfbj ea-/o ddzkgenerated by one engine?

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50#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The intensity at a distance of 6.0 m from a source that 6sa b1s lwx+p 6hjf/v8is radiating equally in all 6sfhxpv81+sa/ w6j bl directions is
$6.0 \times 10^{-10} \; W/m^{2}$. What is the power emitted by the source?

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51#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The intensity at a distance of 6.0 m from a so6h22f n4r uzrource that is radiating equally in all directi6 zh 22unfror4ons is
$6.0 \times 10^{-10} \; W/m^{2}$. What is the intensity level in dB?

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52#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A barking dog delivers about 1 mW of power, which is assumed to be rt lm44vp8/b cuniformly distributed in all directions. What is the intensitpvt rcm4l/4 b8y level at a distance 5.00 m from the dog?

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53#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The intensity level is 65 dB at a distance 5.00 m from a )djew5,kl7hepr2ya) barking dog. What would be the intensity level if two identical dogs va,ywh)dkrle 7 ej2 p5)ery close to each other are barking?

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54#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  At a distance of 15 m from a sound source the intensity level is 60 fy*/ndts9jqn:xnx a 8r6l 6:bdB. What is the intensity level (in dB) ajtfnb :a*:ysn9/nx qlx 8r 6d6t a point 2.0 m from the source? Assume that the source radiates equally in all directions.

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55#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The sound intensity level 5.0 m from a point source is 95 dB. At what distance1v/r0kae 9b3fnvdk t ,ppv /(d will it be 75 dB//3pe, r bvk09 va( tkpvf1ndd?

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56#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The third harmonic of a complex tone7 37rkrg 2*bx mg or54xbszq5l has a frequency of 1200 Hz. What is the frequrklg g2*oq4br7z753rx x5bms ency of the fourth harmonic?

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57#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The frequency of the third harmonic of an open pipe is 900 Hz. What is the leng za4b7w;l mdtso(j; h5th ofw l4h(d5bm; ;a ozstj7 the pipe?

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58#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The lowest tone to resonate in an open pipe of lk1o-t,o8trmefynfsa;o86yaq9: r :k gb5e2 jength L is 400 Hz. What is the frequency of the lowest tone that will :akrea5q12so,ejk yf t;t:6fboy r 88g- 9nmo resonate in an open pipe of length 2L?

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59#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  An organ pipe open a,h 8ltkas7j:yt both ends has a length of 0.80 m. If the velocity of sound in air is 340 m/s, what is the frequency of thk:y8 t7jhl,a se second harmonic?

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60#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 3.00-m long pipe is in a room wsp48;t/b wkgu here the temperature is $20 \; ^{\circ}C$. What is the fundamental
frequency if the pipe is open at both ends?

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61#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The fundamental frequency ic(nd 6blw*,7 n7id4jpmyf (nsn a pipe closed at one end is 330 Hz. What is the freq l7bmnc7 wy(ndfid j(s,6* p4nuency of the third harmonic?

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62#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What is the length of the shortest wk;wq/ s*2qhs pipe closed on one end that will have a fundamental frequency q2h* k /wq;swsof 60 Hz on a day when the velocity of sound is 340 m/s?

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63#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 3.00-m long pipe is in a room whep0 4uohhraq7 jb,d; *vre the temperature is $20 \; ^{\circ}C$. What is the fundamental frequency if the pipe is closed at one end?

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64#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 3.00-m long pipe is in a room where the temps:f xy -pz3 gp16vd;vaerature is $20 \; ^{\circ}C$. What is the frequency of the second harmonic if the pipe is closed at one end?

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65#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A closed organ pipe of length 0.75 m is played when the speed of sound in air is)jtjyrr; (ts)s: j8 xr 340 m/s. What is the fundamental frequenrtrs:(; jyjxjt)s r8)cy?

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66#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Consider two pipes of the same length: one is open and the other is closed o0+p wk w * grvs6ws8d7m6os8txn one end. If the fundamental frequency of the open oss*8wtpmwgs7 vd0rk 6+x 6w8pipe is 300 Hz, what is the fundamental frequency of the closed pipe?

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67#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Two adjacent sources each emit a frequency gdi; c.vg/8c 8afm z:9gxhm*o of 800 Hz in air where the velocity of sound is 340 m/s. How much farther back would source 1 have to be moved so an observer in front of the sources would hearz;xgi/g.a:dgo mchf 988 m* vc no sound?

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68#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Two speakers are placed side by side and2e hp1t5wql9h driven by the same frequency of 500 Hz. If the distance from a person to one speaker is 5.00 m and the person detects little or no sound, which of the following is a possible the distance from the person to the other h12lp9 eh5q wtspeaker? (The sound speed is 340 m/s.)

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69#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Two tunes have frequencies of 440 Hz axu6++wn2r /u4yabe 0:lu eslq nd 444 Hz. What is the beat frequency?

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70#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A music tuner uses a 550-Hz tuni;(e -k fo tz6vop*s0anng fork to tune the frequency of a musical instrument. If the t*t k 6zpo-vfsa;(0eonuner hears a beat frequency of 2 Hz, what is the frequency of the instrument?

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71#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The wavelengths of the sounds produced by two horns are 6 m and 7 m respectivew2 8moek3y-wq 5-igbt 0i9zfl- 3mcgoly. What beabo wq8-0z3mw-l cmt- kfi352y9ie gogt frequency is heard when the horns are sounded on a day when the velocity of sound is 340 m/s?

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72#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The corresponding violin strings on two violins in an orchestra are found to t62 m/z9ngwgzm(gso 3 produce a beat frequency of 2 Hz when a frequency of 660 Hz is played. 3gsomgm 6twg(z /z92nWhat percentage change in the tension of one of the strings would bring them to the same frequency?

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73#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  An observer approaches a stationary 1000-Hz sound source at twice the speed o*.qkl 4)ujal yf sound. Theq yl*)ja4l .uk observer hears a frequency of

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74#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A sound source (normal frequency of 1000 Hz) approaches a stationary observe0: 6vmbx.89;ctxh:juycoaj k r at one-half the speed of sound. The obser 8ycv:bu;t 6aj9m.xco k :hxj0ver hears a frequency of

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75#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A sound has a frequency of 1000 Hz. If a listene9m)gdy ; ydno8r moves with a speed of 30 m/s away from the source, what is the frequency heard by the observer? (The sound speed is 340; dg mny9oy8d) m/s.)

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76#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A police car has an 800-Hz siren. It is traveling at 35 m/s vf pwgb;j9ss28 :d 4rway8 /ufon a day when the speed of sound through air is 340 by4:wr 9;vpfug sd8/ wfa2j8sm/s. The car approaches and passes an observer who is standing along the roadside. What change of frequency does the observer hear?

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77#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What is the frequency heard by a stationary b))-cz- znyrbd 2w8pt f3f.ufobserver when a train approaches with a speed . fnfu-fcwz-by)3bzr)2pt8dof 30 m/s. The frequency of the train horn is 600 Hz and the speed of sound is 340 m/s.

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78#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A train is traveling toward you at 120 km/h. Th8qu55eqwe 6fhc19 7kv8 mvoppe train blows its 400-Hz whistle. Take the speed of sound to be 340 m/s. What frequency dqp8e 7 fvwek8qh vco591m6 u5po you hear?

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79#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  You are moving at 120 u4;t,0 g pdqzwig t)7ikm/h toward a stationary train. The train blows its 400-Hz whistle. Take the speed of sound to be 340 m/s. Whagd,uiw047t p)q z;it gt frequency do you hear?

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80#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A train is traveling away from you at 120 km/h. The train blows (oa cew 5*skh/vs bl giav)tf/,(vz./its 400-Hz whistle. Take the speed of soua (/lc.s5 v/(bhazt,so /vwf) *v iekgnd to be 340 m/s. What frequency do you hear?

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81#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A train is traveling away from you at 120 km/h. It blows its whistle,f 9 bo wrbgwd2rd5why0d/)34 e and you hear a tone of 400 Hz. Take the speed of sound to be 340 m/s. Wwyedh gb/ 02rb 45ow)9d rd3wfhat is the actual frequency of the whistle?

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82#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The frequency of a train horn is 500 Hz. Assume the /m2cxne d1u* :6etxd6-g,b h+vmbpb nspeed of sound in air is 340 m/s. What is the frequency heard by an observer if the observer is moving away from the train mx/b b* ,tde6u+mpc16 dx2nevn-:bghwith a speed of 30.0 m/s?

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83#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The frequency of a train horn is 500 Hz.gi:r +ag r+kqba,:3 u5qluzs ( Assume the speed of sound in air is 340 m/s. What is the frequency heard by an observer if the observer is approaching the train with a speed ozukl+gb3qsga r:5i :rua(+,qf 30.0 m/s?

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84#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Sonar is used to determine the speed oygwh t8pwp.; 20zfy*o4f.m u vf an object. A 40-kHz signal is sent out, and a 42-kHz signal is returned. Assume the speed of 2 4fpp;t* gwvuyy8hf zomw.0.sound is 345 m/s. How fast is the object moving?

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85#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The half angle of the conical shock wave produced by a supersonic airfv88 n o9qza)jcraft is $60^{\circ}$. What is the Mach number of the aircraft?

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86#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A jet flies at a speed of Mach 1.4. What is the half-angle of the conical shoc4nk51r0. uwsoloo i5+ s1vy:kzi0 d-vg im/v bk wav.:5 4 mw- igok/ibs0dlny1k 5u zvr01 v+ivsooe formed?

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87#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The Concord airplane flijrlos j57:sq9 sa49bzer w 2i-vtm6 /ves from the United States to Europe with a Mach number of 12v56sr tslaromq szb4vi/- e99:7j wj.05 where the air temperature is $5.0 \; ^{\circ}C$. What is the speed of the plane?

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