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[单选题]
调试超声波检测仪时，测得t0=5μs，已知某测点声距L=40cm，仪器显示声时为105μs，则超声波在混凝土中传播的声速为（)。
A.3636m/s
B.3810m/s
C.4000m/s
D.4200m/s
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题目内容
（请给出正确答案）
A.3636m/s
B.3810m/s
C.4000m/s
D.4200m/s
答案
更多“调试超声波检测仪时，测得t0=5μs，已知某测点声距L=40cm，仪器显示声时为105μs，则超声波在混凝土中传播的声速为()。”相关的问题
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第11题
C
In period of the summer holidays there will be a revised schedule(修改过的时刻表) of serv-
ices for the students. Changes for dining-room and library service hours and for bus schedules will be posted on the wall outside the dining-hall. Weekly film and concert schedules, which are being arranged(安排) ,will be posted each Wednesday outside the student club.
During the summer holidays, buses going to the town centre will leave the main hall every hour on the half hour during the day. The dining-room will serve three meals a day from 7: 00 a.
m. t0 7: 00 p. m. during the week and two meals from noon t0 7: 00 p. m. on weekends. The li- brary will continue its usual hours dur ing the week, but has shorter hours on Saturdays and Sun- days. The weekend hours are from noon t0 5: 00 p. m.
All students who want to use the library lending services must have a new summer card. This
announcement will also appear in the next week's student newspaper.
64. The main purpose of this text is to ___________.
[ A] tell students of important schedule changes
[ B ] tell students of new bus and library services
[ C ] show the excellent services for students
[ D ] ask students to renew their library cards
