NJC 2022 Waves Notes

National Junior College 2022 2022 | Science | JH4 Bridging Module WAVES Overview Waves are inherent in our everyday lives. Much of our understanding of wave phenomena has been accumulated over the centuries through the study of light (optics) and sound (acoustics). The nature of oscillations in light was only understood when James Clerk Maxwell, in his unification of electricity, magnetism and electromagnetic waves, stated that all electromagnetic fields spread in the form of waves. Using a mathematical model (Maxwell’s equations), he calculated the speed of electromagnetic waves and found it to be close to the speed of light, leading him to make a bold but correct inference that light consists of propagating electromagnetic disturbances. This gave the very nature of electromagnetic waves, and hence its name. In this bridging course, we examine the nature of waves in terms of the coordinated movement of particles. The discussion moves on to wave propagation and its uses by studying the properties of light, electromagnetic waves and sound, as well as their applications in wireless communication, home appliances, medicine and industry. There are 4 topics in this course: 1. General Wave Properties 2. Light 3. Electromagnetic Spectrum 4. Sound

JH4 Bridging Module (2022) 2 Topic 1: General Wave Properties Content • Describing wave motion • Wave terms • Longitudinal and transverse waves Learning Outcomes Students should be able to: (a) describe what is meant by wave motion as illustrated by vibrations in ropes and springs (b) compare transverse and longitudinal waves and give suitable examples of each (c) show understanding that waves transfer energy without transferring matter (d) define speed, frequency, wavelength, period and amplitude (e) recall and apply the relationship velocity = frequency × wavelength to new situations or to solve related problems (f) recall that a ripple tank can be used to demonstrate water waves (g) state what is meant by the term wavefront 1.1 Types of wave motion (a) describe what is meant by wave motion as illustrated by vibrations in ropes and springs (b) compare transverse and longitudinal waves and give suitable examples of each (c) show understanding that waves transfer energy without transferring matter Several kinds of wave motion occur in physics. Mechanical waves are produced by a disturbance, such as a vibrating object, in a material medium and are transmitted by the particles of the medium vibrating about a fixed position. Such waves can be seen or felt and include waves on a rope or spring, water waves and sound waves in air or in other materials. A progressive wave or travelling wave is a disturbance which carries energy from one place to another without transferring matter. There are two types, transverse and longitudinal waves. Transverse waves In a transverse wave, the direction of the disturbance is at right angles to the direction