![sound diffraction and angle of incidence sound diffraction and angle of incidence](https://revisionworld.com/sites/revisionworld.com/files/imce/refraction-glass-block.gif)
However, if you have difficulty with more than two of the Exit questions you are strongly advised to study the whole module. If you have difficulty with only one or two of the questions you should follow the guidance given in the answers and read the relevant parts of the module. If you are sure that you can meet each of these achievements, try the Subsection 7.3Exit test. Study comment Can you answer the following Fast track questions? If you answer the questions successfully you need only glance through the module before looking at the Subsection 7.1Module summary and the Subsection 7.2Achievements. If not, proceed directly to the Subsection 1.3Ready to study? Subsection. If so, try the following Fast track questions. Study comment Having read the introduction you may feel that you are already familiar with the material covered by this module and that you do not need to study it. This final section also contains a few brief references to the nature of musical sounds. Finally, Section 6 shows how the superposition principle can be applied in the case of sound to account for such typical wave phenomena as interference and diffraction. It introduces the related concepts of intensity and intensity level and discusses the measurement of the latter in terms of decibels. Section 5 deals with the energy transported by sound waves. Section 4 concerns reflection and refraction of sound, and explains how these simple phenomena can be put to practical use in medical and other applications. Section 3 concerns the Doppler effect: the dependence of the observed frequency of a sound wave on the relative motion of the sound source and the observer.
![sound diffraction and angle of incidence sound diffraction and angle of incidence](https://radiologykey.com/wp-content/uploads/2017/04/c02-fig-005.jpg)
It also investigates the physical properties of a medium that determine the speed at which sound will propagate, and examines the way in which the properties of sound waves change as they travel from one medium to another. It explains what is meant by a longitudinal wave and lists the properties such as wavelength and frequency that may be used to characterize such a wave. Section 2 explores the nature and characteristics of sound waves. Hearing is a mental phenomenon, influenced by physiological and psychological factors that are still not fully understood, but sound is a purely physical phenomenon, and therefore a very suitable topic for a FLAP module. When the pressure waves arrive at the human ear they cause the vibration of various membranes and bones which in turn activate sensory organs inside the ear that send nerve impulses to the brain. It is these pressure waves that constitute the sound produced by the drum. The vibrations of the drum skin in Figure 1, for example, will cause the air above the drum to move back and forth, thus creating pressure waves that can travel through the surrounding air.