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2010年第二十七届全国中学生物理竞赛预赛试题第18题给出的两个参考答案均有问题,本文提出商榷意见。【原题】超声波流量计是利用液体流速对超声波传播速度的影响来测量液体流速,再通过流速来确定流量的仪器。一种超声波流量计的原理示意图如图1所示。在充满流动液体(管道横截面上各点流P2R2T2P1T1R1图1
2010 twenty-seventh session of the National Physics Physics Contest pre-test questions 18 questions given two reference answers are problems, this paper put forward their views. 【Original】 Ultrasonic flowmeter is the use of liquid flow velocity on the ultrasonic propagation velocity to measure the liquid flow rate, and then through the flow rate to determine the flow of equipment. A schematic diagram of the ultrasonic flowmeter shown in Figure 1. In the full flow of liquid (cross-section of the pipeline flow P2R2T2P1T1R1 Figure 1