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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 false staol4a,pwhg:0a4t ms , a,u8hkgp8r0ze tement?

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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 fastest throm(8nm pg6z). a,8 g5xpuo js7qxv.areugh

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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 stee0to xgtg*nlnukl 96f:l7 9w 3ul 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 incrdd-fr iq*60 +b0g uepteases, what happens to the velocity of sound? uie*drqfd0tp6-b0 g+ (Assume that all other 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 va q1o y1g/9+-cf rpghzelocity of a 200 Hz sound through air arp-qfgg1zy1h+ 9/ o cis

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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 sou,zj7-zcwt voeb2z( i6 nd, the wavelength of a 200 Hz sound in6i-oc2 w t,(evz7zbzj air 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 frequencies greater than 20,05iou 0u2h. aqcl 2pyp600 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 les sj2pv+h0: r-by j4rpts 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 unifv-e;c5niimr4)mg e/dg4 mzelosl3 7mq5 + z;pormly in all directions. If yo4m m-iqc ;zzgp5g so)3 4e r nmid75m+e;/lvleu move 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 proport rc25,rsuwzcfd4x)a5 ional 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 sourc61vtk: s9 smw;;:lxklhdx5zoe at a distance d from the source is I. What is the intensity at a distance 2d from 6mxoz9;wx kkdhlts s :v5:1l;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 thajpkj b+v89ixfm 6f39g t is radiating equally in all directions. What happens to the intensity of the sound? It refpmg8j bk v69x +f39ijduces 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 sou* ,qzked4 (;f1bixos xrce that is radiating equally in all directions. What ha*,oe fxbidxz k4s(;1qppens to the intensity 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 becomes louoz21mr2i 4pnaxcoq /edwh 06 6der?

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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 speprnx .6)p 5*b -omoneyaker emitting a pure tone. What characteristic of the sound increapbyox5 m) .*nr-n6eposes?

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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 musici a ik,)x::buiu/ 7kqtal 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 m5 vw1 ,xxc 4cuarg ,i e.g3hr6b0ogms/usical 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 airi+0 zanbjr ,qk e5v:1o 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 wjq -8 c4ruxspyd .ipkpq/ae ,ctr2--4aves 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 4f-xgxs a h4hghasu yrs37nme 8-+ ;2bwave generated by the guitar as a resx mfnse 8hs 3u;gahs-g r-2xyh7b4+a4ult of this vibration. What do these two 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 at both ends,l i8 c:4nh3szr 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 wa938o x1)usccmgfrx 9f velengths of the three lowest tonescf9g rmc 18f9 )xs3oxu produced by 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. Whichst -o.2*q:hd0awwux e8p6e kr one of the following frequencies will not resonate i8 0s*o6:a2txdeu k.h w-pwrq en 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 fr41z;3awibiv.39 .z th sswy jjequency. Which statement is corj.hyw13it4zsa9v i3sj ; .bzwrect?

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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 andci hag t4ont/l k*)h0i .+di+i 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 of6tbba6tx x-jvw dn)7/ length L. What are the wavelengths of the three lowest tones produced by this pipe?bxajwt 6n 76dt x/)-vb

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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 w3,fzr91 )vhilgy 5ukof length L is 200 Hz. Which of the following frequencies wil, 9)3i1zvfkhu5gr yw 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 one end is resonating( 7dpd3jfm g c ngfr4rh*84q+x at its fundamental frequency. Which statement is cofd x gnmr4dj*+q 73g(4hfrcp 8rrect?

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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 driven by the same source3 tn +.5qgz xvwn:l:qd. Each speaker pron+g.zxw3t5q qdvnl: : duces a tone with a frequency of 200 Hz on a day when the 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-2xuv9dbm13g lywb: m 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 yww 3y62a6jtoand a particular beat frequency is heard. What y6yowjt32w6 ahappens to the beat frequency if the frequency of one of the tones 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 explai:g4 d9w71re wd etoz7cns

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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 9ctfrdy .n(bl)sqd 3 8observer. The frequency heard by the obsrclnd.t8)9bf(y 3 q sderver 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 frevp cku/j gfb(/0vu tsr**+ei/quency heard by the observer (t/**kcrfe usji/+bg 0vp /uvis

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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, its half-angle will dmh- jc8x4un 8aecrease by a factor o8a8 u nh-jm4cxf:

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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 frequeoa kd 2s/434f gd2wsxancy 45 kHz in air is 352 m/s. What is the air temperatud2fas/d 43sax4 g okw2re?

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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 iv(-vdlqbuzo dru - ct6/z y);8n 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 is 340 m/s, a 44rprz/mns,mrz /t9c bat emits a shriek whose echo reaches it 0.0250 s later. How far away was the object that reflectezm/zt cr4rm/ rp49, nsd 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 5;:bh)vyfs33w*hm lb3i atas in 4.00 s. The 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 5.0 s after seeing a flash of 3x87 /zk0s7f uz5 9ni6zeffn bbjnag5lightning, the distance to the lighe3zbb5/k nxaif7zns89z5n6f ju g0 f7tning strike 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 fr.7* v-dkevchrom a cliff on 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 deep well and hear the s x*3j jb*obyl1j4zg2vplash 2.5 s later. How deep is the well? (Ignore air resistancvzgyj3j* 14bbo*l x2 je, 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 soundvuyj+ *. e.vxk wave 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 ai10vw7vequtt qs, y,rvv; x.l v4 v(e,vr 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 levu ek o)as,f(k:6 5 s9xhojbv*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 ,aa e9n*qdy5ih; h -pby1 -qxeof 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 sounds with intensity levels ofks f-+ji: lg4s 70 dB and 40ljsfg+ :k 4-si dB?

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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 1sc ijqf-q,*2v 5 engines in a garage is 100 dB. What is the intensity level generated bsi2qjf,-q * vcy 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 fromgzgj7/ --6iwf 8n4og2noag (der0k pr a source that is radiating equally in geg0286d4rg- nkr/o infz(jg 7 aw p-oall 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 sourc s/adrbbxeb,- 7kw2t8e that is radiating equally in all directi7 ,r2 xsbbtbd8a/w-keons 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 uniformly dis0rrbwlq: j3fd qgnd++k0 /u k:tributed in all directions. Wn:+ddrg qb0 rlfjw/0:3 +u qkkhat is the intensity 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 6g6yfwy)c0c +/wfz ho/5 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 otwgc //y)ow6+ zfchy f0her 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 ta9 vo0qo:96,jdcw mpm 8vq yyzyc(i..he intensity level is 60 dB. What is the intensity level (in dB) at a point 2.0 m from the source? Assume that the source radiates(qdmycz,om9wyy ao 6p08q.v. :v9ci j 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 l km8lo4op57t point source is 95 dB. At what distance will it bp mto 47o58llke 75 dB?

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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 tone629y gal grho. has a frequency of 1200 Hz. What is the frequency.gla2r 6ygh9o 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. ntp .weq i6y6aa2p 0x*What is the length of thpiq y a. xpa02t6e6w*ne 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 o/z xb,ex zjs-z1 98ng:uzjnp2 f length L is 400 Hz. What is the frequency of the lowest tone that will resonate in an opesezjnxz81/-zjpg nzb: 9 u2x ,n 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 len sm4fdtsr (jh x0n7/m/gth of 0.80 m. If the velocity of sound in hss4fnj7/md x0mr(t/ air is 340 m/s, what is the frequency of the 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 wh+pbujfv.ys/;4 yz/ kuere 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 33 n1wau icnpo9/- *x*be0 Hz. What is the frequency of the third harmoni9o *uc/bie xnwp1 *n-ac?

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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 oxceu-3c y0 jcp;17fgv 4dla*sf the shortest pipe closed on one end that will have a fundamental frequenc3ays7g -4u1pc ccjflx;de v* 0y of 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 where the te 8(uhzpp4+ o7 ;o,bt/qvrydgt mperature 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 i+1g lwsn90wzn2ru w -kjq, b7un a room where the temperature 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 hy;e jfwn47n ir81j;f in air is 340 m/sih8y jfr;;ewf 14j7nn. What 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 l4ohvccg6k,5dvel7fnu w9 6l 7ength: one is open and the other is closed on one end. If the fundamental frequency of the op97dl6 e4vk7 uclw,cvhfgn 5o6en 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 a frequency of 800 Hz in air where+6r;4 hz6fq spp 7evtf1q9m vn the velocity of sound is 340 m/s. How much farther back would source 1 have to be moved so an76frp9m f stnve;h+46 qzqvp1 observer 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 by the same frequency o 1xdwt78 l4zfsf 500 Hz. If the distance from a person to one speaker is 4wl xdst1f87z5.00 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 a0ntpr ebj)rdbi2 v o,p./6x f6nd 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 tuning fork to tune the dgowrj h81jc :*gd5b f2 abs9so0k-)yfrequency of a musical instrument. If theo8w9*g0)- 1jd2g fody b:kbsh 5jar cs tuner 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 producedpd qn2 b6)azt+ by two horns are 6 m and 7 m respectively. What beat frequency is heard when the horns are sounded on a day when the veloci pq6 +n)zadb2tty 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 strw775vl1c meki,h pe;z ings on two violins in an orchestra are found to produce a beat frequency of 2 Hz when a frequency of 660 Hz is played. What percentage change in the tension of one of the strings would bri1l zeceh7wk7;vm p5 i,ng 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 approache7;p 4m *ouct.k0ws5bai. qb:uk 0ww kes a stationary 1000-Hz sound source at twice the speed of sound. The o7.wwbqabk*ui4cp t5uow ek0 .;:s k 0mbserver 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) approachese zp41+z (rhv8dmbq vzem99:q a stationary observer at one-half the speed of sound. The observ+1ev9dm 9pqhzrze v(zbm:4 q8er 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. Ifp:7 -u +fzbld rmrf:9b a listener 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 m/s.)z-79rp:fmulr+ : d fbb

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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 8r dx1 oprxfh:f)( 9/owv(ni 0c00-Hz siren. It is traveling at 35 m/s on a day when the speed of sound through air is 340 m/s. The car approaches and passes an observer who is standing along the roadside. What change of frequency does wx)h1 0/(ri xrfdo :fcv(pon9the 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 observer when a train approf0n lch*yqi z ob*t2ni 1cv5jl,99-ecaches with a speed of 30 m/s. The frequency of thov ,htyli5 f cq bin1z92nj0**c9e-lc e 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. Theb)w/klnc bf sd:+7+t tycg:m: train blows its 400-Hz whistle. Take the speed of sound to be 340 m/s. Whatmw+: g)+ktlnsbb/: :fc tdy 7c frequency do 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 km/h toward a stationary train. The train blows its 4o4fo- 5 brrljy5 (:wsg00-Hz wwo ( sgfb:5j-rl45yrohistle. Take the speed of sound to 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 away fromcp1kho ix) r,)v05n mv you at 120 km/h. The train blows its 400-Hz whistle. Take the speed of sound to be 3 k)n5v)xip 0m ,chvr1o40 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, and yogz ekq9iw7ao)8jj g7xe: 6qa9gx qh/;u hear a tone of 400 Hz. Take t8zq )q heaxi:k76o;ge/jj gg79xq9aw he 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. Ass;z2 lve 65lmbxume the speed of sound in air is 340 m/s. What is the frequency heard by xbz6 vm;e2l5l an observer if the observer is moving away from the train with 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. Assume the speed of sound iynyy+ sgy/.sycw 3yy8sv*z2 / n air is 340 m/s. What is yy sgv3y+wy8 /ns. c/yysz*2ythe frequency heard by an 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 determine the 2f iyl 4;yv6h0mbdkw e,(lr (pspeed of an object. A 40-kHz signal is sent out, and a 42-kHz signal is returned. iwkf,hv epl04y26; yrbd((ml 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 conical shock wave produced by a supersoqgstuib q5e:. sd, kkc*rt884nic 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 6dby idv5k njs12 .(oev4o5aliy 5(xqshock wa. iykxd6dj 5 (lv45(nsybqo2aove5 i 1ve 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 flies from the United Stadh*yd8gix x1p44s hc+tes to Europe with a Mach number of 1.05 where the aicipxdg d h+*h4s1x4y8r temperature is $5.0 \; ^{\circ}C$. What is the speed of the plane?

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