单选题 In Figure 2, assuming a uniform beam pattern, what relationship would you expect to edit between the amplitudes of the reflected familiar signal at positions A and B? 图2中，假设均匀声束模式下，分界缺陷的幅度在A和B之间有什么关系？

单选题 When angle-beam contact testing a test piece, increasing the incident angle until the second critical angle is reached may result in: 超声斜射接触检测零件，随着入射角度的增加到达第二临界角会产生：

单选题 The acoustic impedance of a material is used to determine the:
材料的声阻抗用于确定：

单选题 The simple experiment where a stick in a glass of water appears disjointed at the water surface illustrates the phenomenon of: 一根筷子放在水中，在水的表面出现错位，这种现象说明：

单选题 The wave mode that has multiple or varying wave velocities is: 多种或者变化的波速的波，模式是：

单选题 Acoustic energy propagates in different modes. Which of the following represents a mode? 声能以不同模式传播，以下哪个代表波的一个传播模式？

单选题 Which of the following would be considered application(s) of ultrasonic techniques? 以下哪个选项被认为是超声波检测技术的应用？

单选题 The crystal thickness and transducer frequency are related. The thinner the crystal, the: 换头的晶片厚度与频率相关，越薄：

单选题 The only significant sound wave mode that travels through a liquid is a: 在液体中只能传播的波的模式是：