Which one of the following principles of physics is primarily used in sonography (ultrasound imaging), a medical diagnostic process?

Ultrasonic waves produced in air by a vibrating quartz crystal are an example of ______ wave motion.

The phenomenon called a 'sonic boom' is most directly caused by:

Which of the following statements is/are true regarding the speed of sound? (i) The speed of sound decreases with an increase in the temperature of the medium. (ii) The speed of sound in solid state is greater than the speed of sound in gaseous state under the same external conditions. (iii) The speed of sound is independent of the properties of the medium through which it travels.