TJC 10 Waves

Student’s copy 2025 Temasek Junior College Mrs Poon SC Unit 10: Wave Motion Learning Outcomes Candidates should be able to: (a) show an understanding of and use the terms displacement, amplitude, period, frequency, phase difference, wavelength and speed (b) deduce, from the definitions of speed, frequency and wavelength, the equation v = f λ (c) recall and use the equation v = f λ (d) show an understanding that energy is transferred due to a progressive wave (e) recall and use the relationship, intensity ∝ (amplitude)2 (f) show an understanding of and apply the concept that wave from a point source and travelling without loss of energy obeys an inverse square law to solve problems (g) analyse and interpret graphical representations of transverse and longitudinal waves (h) show an understanding that polarisation is a phenomenon associated with transverse waves (i) recall and use Malus’ law (intensity ∝ cos2θ) to calculate the amplitude and intensity of a plane polarised electromagnetic wave after transmission through a polarising filter (j) determine the frequency of sound using a calibrated oscilloscope (k) determine the wavelength of sound using stationary waves. *(l) explain the formation of a stationary wave using a graphical method, and identify nodes and antinodes *(m) show an understanding of experiments which demonstrate stationary waves using microwaves, stretched strings and air columns *learning outcomes of topic of Superposition

2 1 INTRODUCTION A wave is initiated by a vibrating object (the source) and it travels away from the object. The particles of the medium vibrate about their rest position at the same frequency as the source. The wave transfers energy between two points in a medium without any net transfer of the matter or material in the medium. 2 PROGRESSIVE WAVES LO(d) A progressive wave transfers energy from one place to another without the transfer of medium. Sound waves, waves on a string, electromagnetic waves etc are progressive waves by nature. Mechanical waves require a medium, such as string or air, to travel; whereas electromagnetic waves can travel through a vacuum, without any medium. (Read Appendix A for EM waves). Progressive waves can be further classified into transverse and longitudinal waves. 2.1 Transverse Waves Transverse waves are waves in which the oscillation of the particles of the medium is perpendicular to the direction of energy transfer. The passage of a wave through a medium can be demonstrated using a 'slinky' spring. If the spring is subjected to a repeated up and down motion, a transverse wave is set up. The individual parts of the spring oscillate in the vertical plane while the wave transfer energy horizontally along the spring as shown in the figure abov