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F4a • Unit 3
1 Concepts

Wave Motion

Unit Overview

This topic examines the basic nature and properties of waves. Light and sound, in particular, are also studied in detail. Students are familiar with examples of energy being transmitted from one place to another, together with the transfer of matter. In this topic, the concept of waves as a means of transmitting energy without transferring matter is emphasised. The foundations for describing wave motion with physics terminology are laid. Students learn the graphical representations of travelling waves. The basic properties and characteristics displayed by waves are examined; reflection, refraction, diffraction and interference are studied, using simple wavefront diagrams. Students acquire specific knowledge about light in two important aspects. The characteristics of light as a part of the electromagnetic spectrum are studied. Also, the linear propagation of light in the absence of significant diffraction and interference effects is used to explain image formation in the domain of geometrical optics. The formation of real and virtual images using mirrors and lenses is studied with construction rules for light rays. Sound as an example of longitudinal waves is examined and its general properties are compared with those of light waves. Students also learn about ultrasound. descriptions of musical notes are related to the terminology of waves. The general The effects of noise pollution and the importance of acoustic protection are also studied.

Key Concepts

1

Position, Displacement, Scalars and Vectors

位置、位移、標量與向量

Describing where things are and how they move: distance vs displacement, scalar vs vector quantities, and reading motion from displacement–time graphs.

!
Common Pitfall“Distance and displacement are always the same number after any journey”
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