UltrasoUnd Physics & instrUmentation - Pegasus Lectures

3. Classification of Waves .........................................................................................................................82
3.1 Benefit to Classifications .............................................................................................................82
3.2 Electromagnetic (EM) Waves ......................................................................................................83
3.3 Mechanical Waves .......................................................................................................................83
4. Conceptual Questions ............................................................................................................................84
5. Propagation of Mechanical Waves ........................................................................................................84
5.1 Transverse Waves ........................................................................................................................84
5.2 Longitudinal Waves .....................................................................................................................85
5.2.1 Definition and Depiction ................................................................................................85
5.2.2 Developing a More Thorough Understanding of Longitudinal Waves ..........................86
5.3 Problems with Static Drawings of Waves ...................................................................................86
6. Variations in the Medium with Propagation (Acoustic Variables) ........................................................88
6.1 Pressure ........................................................................................................................................88
6.2 Density .........................................................................................................................................89
6.2.1 The Equation for Density ..............................................................................................89
6.2.2 Density as an Acoustic Variable .....................................................................................89
6.3 Temperature .................................................................................................................................89
6.3.1 Generation of Heat ........................................................................................................89
6.3.2 Measuring Temperature .................................................................................................90
6.4 Particle Motion ...........................................................................................................................90
7. Conceptual Questions ............................................................................................................................90
8. Wave Characteristics and Parameters ....................................................................................................92
8.1 General.........................................................................................................................................92
8.2 Four Basic Parameters and the Many Associated Parameters .....................................................92
8.3 Frequency (f) and Period (P) .......................................................................................................93
8.3.1 General ...........................................................................................................................93
8.3.2 Frequency of a Sound Wave ..........................................................................................93
8.3.3 Graphical Depiction of Frequency .................................................................................93
8.3.4 Determining the Frequency ...........................................................................................94
8.3.5 The Relationship Between Time (Period) and Frequency .............................................94
8.3.6 Interpreting the Period ...................................................................................................95
8.4 Propagation Velocity ....................................................................................................................96
8.4.1 Defining Speed and Velocity ..........................................................................................96
8.4.2 Units and Graphical Representation ..............................................................................96
8.4.3 What Determines the Speed of Sound ...........................................................................96
8.4.4 Graphical Depiction of Propagation Speed for Sound Waves .......................................97
8.5 Wavelength ..................................................................................................................................98
8.5.1 Definition .......................................................................................................................98
8.5.2 Graphical Representation ...............................................................................................99
8.5.3 Distinguishing the Wavelength from the Period ............................................................99
8.5.4 What Determines the Wavelength................................................................................100
8.5.5 The Wavelength Equation ............................................................................................101
8.5.6 Different Ways of Remembering the Wavelength Equation ........................................101
8.6 Amplitude ..................................................................................................................................102
8.6.1 Definition .....................................................................................................................102
8.6.2 Units .............................................................................................................................102
8.6.3 Graphical Representation .............................................................................................102
8.6.4 Calculating the Amplitude ...........................................................................................103
9. Conceptual Questions ..........................................................................................................................105
Pegasus Lectures, Inc.
xv
Table of Contents