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习题练习：Physics Unit12: Sound
本习题练习来源于51fly国际课程 (https://51fly.win)，是在线习题练习的打印版，您也可以访问本平台网站(https://51fly.win/)直接在线完成(注册并登录账号后在首页左侧输入试卷号 70 即可在线作答)，，作答电子化后可随时回放，查看每题答案与详细解析，搜藏保存任意题目；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。本试卷的直接作答链接 https://51fly.win/test70.html
 作者: physics  发布日期: 2022-09-26 09:56    总分: 87分  得分: _____________

答题人: 匿名未登录  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 stam;2f7 3oc advttement?

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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 dmh22.vb+qj s( gu3cqthrough

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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 steo+ww; qp-d2* z(mzp dfel 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 increases, what happens to the velsu-sm(ui1 n+,lnaj x5(i ts6 socity of sound? 6ns ( iu1 ,x sn-5mstjl+i(aus (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 velocity of a 200 Hz sou ,m1pqptebs. st; a()dnd through airt)atqp;,m s sde.b(1p 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 Hzo+ zjt tyezfj,/ w3*q3 sound, the wavelength of a 200 Hz sound in oy+ 3,/ eqjj 3*ftztzwair 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 greatd siyf q9( uyzzt(5(.der 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 ,yv 7*y6/ vm wffpsxr g1*nn0f/i:gmcless 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 wavjxo e4iiyf slv40: :3les uniformly in all directions. If you move to a point twice as far away fxy44i 0:esij lf:o3vl rom 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, .w)h,we e.4woi l ezh8intensity is proportional 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 poihlcy :hr, c) lhdo4+6w pg5y1;ujsn;cnt source at a distance d from the source is I. What is the intensity at a distagh6;)dy4o c p1;lhr:h+cjlnu , sc 5ywnce 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 sou0coydv,0/,xmur: m7xg 9j aziims34vnd source that is radiating equally in all direct : smg,m mi xruo yc9j70v/4ixdv,az30ions. What happens to the intensity 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 4rz66,0 naf(gf* im ybnqi z8wa sound source that is radiating equally in all directions. bf wn* rzyz,g aq(6 6iif40m8nWhat happens 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 inu2vkvd9x4m/nk3 ojazwt* -8 wcreases as a sound 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 i3:wmd tmslvb*.43z cpure tone. What characteristic of the sound increalsw.4* bdmi 3:tz mc3vses?

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16#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What determines "loudness" o/lhu mkig6:l9f 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 notjvw* ev/ givk,trm *d*+a9g; me?

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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 air(zg wx( 5xfwjlo2 3i;qt.ilo9b.5 nsh 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 displace r4 8e,h9e4-e+kg okrxx: vtykment 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 soug5rn2cmzd of6t6 m 8-lq60flk nd wave generated by the guitar as a result of this vibrdklf-n6zom 6m8 fl 25gct06qration. 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, they94o*btn wjt; re

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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 8x4j 7zyl qgu+ngeul,1 bbq 5*wavelengths of the three lowest to zyexu+7b1lgn4gl* 5qq8bu,j nes 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.v* in2pdz +8p2uj-crw Which one of the following frequencies will nc8+-pwr dv u2*2zpinjot 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 frequenc;4xzt (4n00eegru*xt uguid8 b2yd. ux6h dn;y. Which statement is bz8eyu.eg itud d00x4h nu xr; t(2d4 6g*xun;correct?

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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 gse 5s,q0zq0nend and 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 lenbvuai*q 8vdm r2)/n v8gth L. What are the wavelengths of the three lowest tones produced by this 8anb* viu 8rvdq)/2vmpipe?

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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 length L is 200 Hz. Which tddxv0j;x3x . of the following freque. x0dx3tjv xd;ncies will 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 at its fundamental x*qroh,uh6 jdldg194i ( opnv2 dfo)uq:6na7 frequency. Which statement is correct?n q72od(hqrxoolp) 91giju6d6 ,vunh*adf:4

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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 speakerswrwr) o*.s. mi driven by the same source. Each speaker produces a tone with a frequency of 200 Hzo w. sr.mir)w* 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 d cn,qty 7x7 /r y(agemz,1g9qev6m x,beats, the two sound waves 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 anuf5cc8:z4 ln+h:q +psz eh;tpd a particular beat frequency is heard. What happens to the beat frequency if 5hen8z+u ht;c fc:l+ p:zp4sqthe 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 explaiuh t43yrxy; mi-o2tb56 n7imfns

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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 fren2*hz28y3 rnwcwyybvu- r1.kquency heard by the obser b ky.1vwy2rnyz h8u3r -2*ncwver 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 by the o 5sn 7ja(bn4gabsej4 5nabgn (7sarver 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-speed, its half-angle will a3 de,7 e:*td7ow7 4zz(gsnkt r5kexhdecrease by a factr7tee:nkg7 k,szea5 w d7t4(o3 dxz* hor 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 frequency4a n,-) vvey-3hun6b vue/cvy 45 kHz in air is 352 m/s. What is the air tempe3a nnv4ey/6- vy)h, cbvevuu-rature?

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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 air att6y3ci779jhuu xp 27au( r zmy $0 \; ^{\circ}C$ 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 e gvey;ypy/t5 p* +piy(mits a shriek whose echo reaches it 0.0250 s later. How far away was the object that reflgept/iy*5y( +pypv; yected 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 hm0d837;w z4)tilsnrxlsv+ t zear the echo 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 lightning, the distance to thtmeb fkmx4(ur+ t1 52ce lightning strike is a bttf4m+(cremx2 u15 kbout

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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 kw+35.p xg l 7yj/xvmsday 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 a(x7,afnu h2ee,7zf.brn1d i l nd hear the splash 2.5 s later. How deep is the well? (Ignore air,fu7 l.beze(f7nxri21ha n,d resistance, 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 soo v(rfr h;bk dw mb(f5q)ca)7+und 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 aill4i h cih*x9nxjv1 +ip0s -0lr 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 levmn) 8sktun mwfj0bzzz8n9 )2,el 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 uu(. mfv ,qbu2of 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 2ct( ii iz4 u :x-oi.0in1dnvilevels of 70 dB and 40 dcuinz-ii:2ionvd(it 0x i1.4 B?

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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 dBm (/w1 *jruwcz. What is the intensity level generated by w1 z/cjm (*rwuone 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 is radphx-aw zo- 8;siating equally in all directiohz p sxa-w;-8ons 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 souiyv 583o2d qp4pr.r;gl -h czurce that is radiating equally in all dir8 rh.-ig u;zlqrc3 25pp v4oydections 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, whic seezz6) j6nn1 k8,v5q5urpzth is assumed to be uniformly distributez nj6 k)vsqr8z6 u penz1e55t,d in all directions. What 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 65 dB at a distanskf.3f /b .w l2plzbm,ce 5.00 m from a barking dog. What would be the intensity level if two identical dogs very close to each other arefbmp l.bl 3w.kf/z ,s2 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 from8nt :nr.thpk);g tbe 4 a sound source the 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 equally in all directih8g ;n nrb:.4tptt)ekons.

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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 wh 064l qz94owfxkkon2xat distance will it b 4x0k4nfqx 9klzo 26woe 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 tone has a frequency of 1200 Hz. Whavbg-b5i3l;vl *vn *mut is the frvi5;*mv lvn* 3-bugb lequency 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 Hhi 7m zsg*zx/*97ib svsaho g +0q.2hsz. What is the length of the pipe ih*.*gqz72 z9b7v0ssa h ixo/s smh+g?

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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 length L is 400 Hz. What xtrror 6/;4dkv9v c4b.jolmy*.wp 0z is the frequency of the lowest tone that will resop* m4o y.v4/trbr c9.wx zk6;vjrl0odnate 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 n u x cy:v;bee5v+ u+)natk.)lof 0.80 m. If the velocity of sound in air bvnv. u tae)+ck);5yl exn u+: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 where the tepnk,mt, l2(sk mperature 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 +ukdo8b7r(xh* -kz- epq t(mh. What is the frzx(bp*ekmd qokt7- hu- +h(r8 equency 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 pi/g-2 sf xta eo*38n:fnmxcz;e pe closed on one end that will have a fundamental frequen;-2a g:e/efzc*txn3sofmx 8 ncy 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 g7 j sjq1y g2 f1yeaz0;q;o5sqwhere 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 temperatic1 :llmxi7x7u9 s9u aure 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 bpgkg.+fuzvm-dh26;bq7 eidcd 2 9r 6the speed of sound in air is 340 m/s. What is the be drpgzb2 67dq. i;fudk6v+h 2c9- mgfundamental 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 onzyr n;wp90f u/ 2w j,wl) af7ht.ib/rther is closed on one end. If the fundamental frequenc7jnwp.wayzi u; bf,n/0hw9 l2 r)ftr/y 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 a frequency j(s5 m p9zg1r-3s) e xkl2nluyhtm:v 0of 800 Hz in air where the velocity of sound is 340 m/s. How much fart0l2)zt: ku9mrvyxeh 3pns- jms (1 l5gher back would source 1 have to be moved so an 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 of 50+, e ) v9jov6tnjg.aqq0 Hz. If the distance from a person to one speaker v)a 9n6qgveoq , jt.+jis 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 k/be;(5 ec n,z+kmeudyb(a-zHz. 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 tj22zw6qgqbce0 3m/ fdnc x,6uo tune the frequency of a musical instrument. If the tuner he2fnc/ xczm,d g6b6eqq02 wu3jars 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 ouu5x sqx:7e1c*k7yprespectively. What beat frequency is heard when the horns are sounded on a q 7cp5oey x: xus*u1k7day 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 stj6 k (,usjsphl5m04 2rzc-zlyrings 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 z zrm ju5ls0k2, 4yj-hc lps6(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 au5m-t t-w. re1000-Hz sound source at twice the speed of sound. The observer hears a frequency .trtwe5 amu-- 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 freq 3 rq5ax,6frs5kxurl7 bqni( ,uency of 1000 Hz) approaches a stationary observer at one-half the speed of sounixl5 x rrf6q7b,a, (nq35sukrd. 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 qa(wg*f1 f:(u up4e dgmoves with a speed of 30 m/s away from the source, what is the frequency heard by theg:(d*e ( ff1uauq gpw4 observer? (The sound speed 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 siren. It is travel p+i/oq*ooc:v ing at 35 m/s on a day when the speed of sound iq*c o/ovo p+:through air is 340 m/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 observer 0v5p gv ygt5xjldfv :0.16xgs when a train approaches with a speed of 30 m/s. The frequency of the train horn is 600 Hz anv5fj6 pxtv :l0gv . xy5sdg10gd 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. The train blows its 400-b r-am28 gv j2bsg48smHz whistle. Take the speed of sound to b 8s am24g bj2s-mv8rbge 340 m/s. What 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. byhfnb 6,)j h+:x8m(w )ge (.dzeavus The train blows its 400-Hz whistle. Take the speed of sound u z v(wefe.x)a)8(b 6b,hdjg:s n yh+mto 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 from you at 1tz*q926uy e mc20 km/h. The train blows its 400-Hz whistle. Take the speed of sound to be 340 m/s. What frequency do *mz2 te6uqc9 yyou 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 whe4luvne j m* f/71;.1nlggnm lp-jfx1istle, and you hear a tone of 400 Hz. Take the speed of so vffx4gne1.jm* luln/ 1pjg-n 1;ml e7und 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. Assume the speed of stv e+g, hp6yg2j +a6 rjb, cvzh;ec6e(ound 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 speed of 30;cejrg(, htp vzcja2he ,6+6e 6yv +gb.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 t x)f; ;jm.hfms; ewv.u0gf( uhrain horn is 500 Hz. Assume the speed of sound in air is 340 m/s. What is the freh;u.husffe0v g f.w;( mxjm);quency 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 sp8 2 w y/dk0ci9pgmd)rheed of an object. A 40-kHz signal is sent out, and a 42-kHz signal is returned. Assume the speed of sound is 345 m/s. How fast is t 2d mkh9ypg/d r)c8i0whe 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 zdde(z2-zku2 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 shodsapdmky c,7 ;j182ky ck wdkka yp8 1;,jd m7csy2ave 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 States to;ish+u t9b3xj8/ w yar Europe with a Mach number of 1.05 where the air temperaaswh+y38;u9it /xb jrture is $5.0 \; ^{\circ}C$. What is the speed of the plane?

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