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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://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://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 following is a rvq-r855olwj 7e k6qe mcz-3dfalse 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 fasteste/ tx;zk; *y;8me slst 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 s u-*ng/+ pf6ws5hne ghound in a steel 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 ofbezbg4ei u05* the air increases, what happens to the velocity of sound? (Assume that all othez4eg5bbi * 0eur 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 n830igtze-53grc at lHz sound, the velocity of a 200 Hz sound throughc5e0tgr8i ngl ta3-z3 air 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 onk jb2-9roy3 lgd ;;neh(o.wsound, the wavelength of a 200 Hz sound in airng-n(9boh3 klo;d e. ;2oywrj 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 frevt 99-ly jrdk8quencies 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 larxunn;run;l 1z)w(y+yk*v hu )q/5 frequency less than 20 Hz are called

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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 source is emitting waves uniformly in all directionsee )vi4a1 u11x:j6xlhon a :. 9knfvgs. If you move to a point twice as far away from the source,1 knoea.vs4j1i 9xle g:xv:uf6)a1nh 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 proportional t*nld1mle 0vfp )hsl n; /r9ul*o

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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 at a dis4r1;472 ba3plx qif mg1tjqkrtance d from the source is I. What is the intensity agbfr;127jl3ip q xqrat414 mkt 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 yc)3nxh)lo*zo)( k- nlxu7 x gis radiating equally in all directions. What happens to the intenoxu )-x(ng)o)z* ky7c3nhxllsity of the 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 sound sourcew39q t k jirngpj mlz6ti87/1t* kp32b that is radiating equally in all directions. What happens to the intensity level of tlipm2 9n j kjgtb3*i/p z8kr7q6w3t1the 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 ssn+s4+ v(xfg vound becomes 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 p;3 5mkcdcth o l+j7wj6ure tone. What characteristic of the so t ch76 ckjlj35m+wd;ound increases?

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16#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What determines "loudness" of a mus(iz+ +b2 wuw,3p9iojoa5s fqm,v k0 wtical 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 gs wfj .h3e1lown xu0fl-)f;2 musical note?

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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 npjxl mk-, v-wlv i;3)air 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 displacemen4awo1+ xc m1hlt waves 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 string and the sound wave p3eyain4a //bac ho81generated by the guitar as a result of this vibration. What do these two waves have in 4ip//nhaye8acoa 3 1bcommon?

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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 at both ends, therej e uz0fqc9p;;7s w0ag/n;5h1 92rw une yvuzy

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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 -7q3z 02xu yh rlrpi3uare the wavelengths of the three lowest tones produced by this 0uz7hirr u-3 y32lqxp 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 pipeahu+yiwz64 f)fwk :tx-m3 gey7b06 gc of length L is 200 Hz. Which one of the following frequenwxkac:73e4 i m6y 6yutgfwzbg)-+hf 0cies will not resonate 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 resonating at its fundamental pg+bq;x kdj.bbz)9qohq9 i3 39jcsz.frequency. Which statement is cob3hd ;iqb9qjb9o qzgp. +3 )zj .9xcskrrect?

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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 andzu jl)x7c2nfl( - qi3m closed at the other, 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 lee*c(wg8 1 qew0yfcl ;qngth L. What are the wavelengths of the three lowest tones produwqg(8 e*cefq1 l0;cwyced by this 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 pipe of len9*joy69sgnn a afz x./gth L is 200 Hz. Which of the following frequencies wi oaaf.96jsg*n nz9yx/ll 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 closed at.mj i,)fn4f-lzf *(yatk i+qq one end is resonating at its fundamental frequency. Which stam-ffqjik +zi l t,*y f.)a(q4ntement is correct?

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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 ;g .xi;go+mrzxr3 y0koo5 puxi- 96ft two speakers driven by the same source. Each speaker produces a tone with a frequency of 200 Hz on a day when therofoykomii+x 9x3 p;zu6;.r gt0 5-g x speed of sound is 330 m/s. The 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 waves should ea*ykvg15f;hjq o 6s(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 particj*i4nffq :z:pular beat frequency is heard. What happens to the beat frequency if the frequency of one of the tones* ifznf:q 4p:j is increased?

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32#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The Doppler shift explainslhr)z.pw9+y3 pp ;pa h

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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 ob7.v)xdl 0gomu h/2lca server. The frequency heard by the observer is2/ v lglh7oud)xam.0c

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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 frop/bhcb)c: *o ez(vhyfe j8*j5 m a stationary observer. The frequency heard by the observer i *evbec8f5bj*hczp( /yo) hj :s

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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-speed, is2c60g y0)l)3vrmvv u8luagz ts half-angle will decrease by a facto) 8sgm2a)z0yvc6g rvv0l u3 lur 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 frp .sn)si8zs 8b3ese 3yequency 45 kHz in air is 352 m/s. What is the ai)ysb 833spe8ine .s szr 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 the speed of sound in a09ew:sz )fywuilz( x *ir 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 is 340 m/s, a bat emits a shri -;etu/8ix+e oibbmuf7ir3e (ek whose echo f+8be37oie-ueb (x;irit /m u reaches it 0.0250 s later. How far away was the object that reflected back the sound?

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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. Th6e* j07p- n1apjtuthse temperature 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.we,71pl, m-s:sn )1 jb)q+ cnwsfc eki0 s after seeing a flash of lightning, the distance to the lightning strike is bq)7ssnjsk lf),+-pm 1 :ee1 niwccw,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 l/gll xxwgqs.fm:-g( tl +x,2p x0,pton a day the temperature is $15 \; ^{\circ}C$. 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 p7 7j 2idy.r/pa( v6d)s lscdvdeep well and hear the splash 2.5 s later. How deep is the well? (Ignore air resistance,s2 dyp7d. l(sv v6p7j/dcira) and assume the velocity 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 of frequencyv/o 9q1 wj0 cfascra43 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 airmfrlwo gn;u 03w(6t9r at $23 \; ^{\circ}C$ 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 lev xjrbg 3tdl*uwxjgf/ 41(b zi (o7n9*bzl.e)iel of a sound 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 fl odc 9(*gcqp586uorh ob(9vof 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 of two souns,e ncrmm;ac:4y b*(tds with intensity levels of 70 dB and 40 dB?:e*bnc mym sr4c;t,a(

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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 1:y0efctp /hshh999ic5 engines in a garage is 100 dB. What is the intensity level generated by one eny 0fshhh e/t:99c9cipgine?

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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 e 6es4 (twn7xdwqzu4+xa9lwi (v ,d/ ofrom a source that is radiating equally in all directions wi/w nz6a+u4l(4dw (7vx9 qt,exdoes 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 distu/u 0lbt1ufrh +d*. (e;ke endance of 6.0 m from a source that is radiating equally in all direction+dr(e b. euf/*uu h1 0;dtlneks 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 uniforiuu 3gfk x74:hmly distributed in all directions. What is the intensity level at a distance 5.00 h7igxku:f4u 3 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 65ni;et3ip: wd8 dB at a distance 5.00 m from a barking dog. What would be the intensity level if two identical dogs very close to each o tipnid:e;8w3ther 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 dB.m 2lnx:btx9t(jew b7 s/7et n5 What is theb t9sewjx: /en2m 77tb xtln5( intensity level (in dB) at 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 sol-afc 42gb u k7*f)wwfurce is 95 dB. At what distance will it be 75 dB-fl7wfbc4 *fawg)k 2u ?

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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 tone has a frequency of 1200 ffdjni7w +,*xHz. What is the frequency of the fourth harmonwj ,+xf7idfn* ic?

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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 ha,r+lll3 goriyu7 ar0.rmonic of an open pipe is 900 Hz. What is the lengtru,i. y0g7o+ a3 lllrrh of 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 resonaotgxh69:5dhn yfjv .;(qv7ze te in an open pipe of length L is 400 Hz. What is the frequency of the lowest tone ttqefh 6x dnv;(h j. o75gvz9:yhat will 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 at both ends has a length of 0.80 m. If the veb;8pat f- 4o4;okotjulocity of sound in air is 340 m/s, what is the frequency of the second harmotp u- ajb;8o4o;to4kf nic?

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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 adtr6n: fk078*jga gcw+ - homo room where 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 in a pipe closed at one end is 330 Hz. What i )i:eiktl ,;)x/oot9)t rbp rjs the frequency of the thir)ket,9 x;r :jipitb/)o lt)ord 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 pipe closed on one end that willlox gm2v1r8l9 ee:i ;v have a fundamental frequency of 60 Hz on a day when the velocity 1 xolli;rem : gvv28e9of 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 where the twmuw8d,pm9z *pl zx, 8emperature 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 temperatureuz6 hlp;le wo2/h,5iqu t0,wt 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 r,g.7*w.0 jm wfrde9e lr3uvlspeed of sound in air is 340 m/s. What.rwfew0de, 3l u7 lrg.m9rjv* is the fundamental frequency?

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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 itbu8t kp. :pt-s closed on one end. If the fundamental frequenbup-:ktt 8p.t cy of the open pipe 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 r3 xbmiw0 i0)*,dc eg*;rvhoha frequency 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 ie;wioh 0r30b m*gvd,c r) x*hobserver in front of the sources would hear 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 and driven bw/x6 x:q y7sl 8lbdpi/y the same frequency of 500 Hz. Ixbsq6pw 7yx 8l/ild/:f 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 speaker? (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 and 444 Hz. What is the bean8gm;ab/p2tgn kg +0ot 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 tuning ,-bkn4 mnv7 xufork to tune the frequency of a musical instrument. If the tuner hears a beat frequency of 2 Hz, what is the frequency of the inbvkn-m4,n u7xstrument?

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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 hor9 + n6senz:j*yif 4ytyns are 6 m and 7 m respectively. What beat frequency is heard when the horns are sounded on a day when the velocity of sound is n*y ynt+9fj esz64iy :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 violinxr 2mmw22pu(ds in an orchestra are found to produce a beat frequency of 2 Hz when a frequency of 660 Hz is played. Whadum2( p2mxwr2 t 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 sv/vu a8 -kk qfku+,(rqource at twice the speed of sound. The observer hears a frequency o vur/kua k-q8qfk+ v(,f

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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 statio:nufp)xh07 . a +jay9gz6bhrbnary observer at jh abb.)uypn grx +zaf7: 60h9one-half the speed of sound. The observer 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 listener moves with fkb .w0axbg+k.hp v*8a speed of 30 m/s away from the source, what is the frequency heard by the observer? (The sound speedhkak. x+0wbgpv.*8fb is 340 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 sl07n45mq5 ro kocc/ktk, q gh/iren. It is traveling at 35 m/s on a day when the speed of sound through air is 340 m/s. The car approac /7 kg45c c,qkr/nqohm0l5okthes 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 stv ;zjkgi+kcl1u96c j ) xki36xationary observer when a train approaches with a speed of 30 m/s. The frequency of the train horn is 600 Hz and thivjkxci g 6 uxz+lk1 6k39c;j)e 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. The train blowo91ajx a; di: abgdxx0itp;13: p grm2s its 400-Hz whistle. Take the speed of sound to be 340 m/s. What frequency do t i1x3p x aair1:;xobmgp:90ad 2;jdgyou 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 km/h td b7r qu+k je(.kl;-aooward a stationary train. The train blows its 400-Hz whistle. Take the speed of sound ebk u ;la-jr+o7. (qkdto be 340 m/s. What 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 awayus)m g, r)tysyq4 2*k)cq m1jf from you at 120 km/h. The train blows its 400-Hz whistle. Take the speed of sound to be 340 m/s. What frequen mqtmjfuys sc2 ))4)yk *1rq,gcy 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 zgu l*sowq 0g7qt.0qnsfid eq2.36wd* l4cn) blows its whistle, and you hear a tone of 400 Hz. Takn n dqw )l0 t*cgz dq74qwgiu6lqe.o2f0ss3*.e the speed of sound to be 340 m/s. What 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. Assumedr o0ha*hoips/++ ui/w.* l xq the speed 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 with a sao0*uqpx i /.h+hiwo/* sd+lrpeed 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 traigt kef(jg0 t;3: pn5lgn horn is 500 Hz. Assume the speed of sound in air is 340 m/s. What is the frequency heard by an:ge lgt jt k3;ng(5pf0 observer if the observer is approaching the train with a speed of 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 determini-3 ppb, .k rqj6-u6mr twe*ooe the speed of an object. A 40-kHz signal is sent out, and a 42-kHz signal is retue*u,op tp.k63j -m ri6br-woqrned. Assume the speed of 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 conicaluzs0no+ tra7/ jm9:kqq/4wca shock wave produced by a supersonic aircraft 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 )8 diqg(ohwu)shock wave wdu ))8gh(oqi 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 fld-ss1d ew8)6van+ odlies from the United States to Europe with a Mach number of 1.05 whe+8 sdw6o1e asdv-n )ldre the air temperature is $5.0 \; ^{\circ}C$. What is the speed of the plane?

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