4.4+WAVE+CHARACTERISTICS

Back to IB PHYSICS > OSCILLATIONS AND WAVES =4.4 WAVE CHARACTERISTICS= 4.1 KINEMATICS OF SHM 4.2 ENERGY CHANGES DURING SHM 4.3 FORCED OSCILLATION AND RESONANCE 4.5 WAVE PROPERTIES
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[|WAVE EQUATION EXPLAINED] - this is calculus! If you like maths, you might enjoy this post-IB idea.

Describe a wave pulse and a continuous progressive (travelling) wave.



Students should be able to distinguish between oscillations and wave motion, and appreciate that, in many examples, the oscillations of the particles are simple harmonic.

OSCILLATIONS: A repeated back and forth motion. CYCLE: One complete oscillation. TRAVELLING WAVE: A disturbance moving from a source and transferring energy from one point to another.

State that progressive (travelling) waves transfer energy. Students should understand that there is no net motion of the medium through which the wave travels. media type="custom" key="25958918"

Describe and give examples of transverse and of longitudinal waves. TRANSVERSE WAVE: Where the disturbance is at right angles to the direction of travel of the wave. LONGITUDINAL WAVE: Where the disturbance is parallel to the direction of travel of the wave. Students should describe the waves in terms of the direction of oscillation of particles in the wave relative to the direction of transfer of energy by the wave. Students should know that sound waves are longitudinal, that light waves are transverse and that transverse waves cannot be propagated in gases. media type="custom" key="25864168" Describe waves in two dimensions, including the concepts of wavefronts and of rays.

WAVEFRONT: A line of surface which joins all points which have the same displacement at the same moment (they are all in phase).

RAY: A line at right angles to the wavefronts which shows the direction of energy travel of the wave.





Describe the terms crest, trough, compression and rarefaction. CREST AND TROUGH: For a transverse water wave, the maximum and minimum displacements. COMPRESSION AND RAREFACTION: For a longitudinal wave, points of maximum and minimum density of the medium.

Define the terms //displacement//, //amplitude//, //frequency//, //period//, //wavelength//, //wave speed// and //intensity//.

DISPLACEMENT: The distance of the disturbance measured from its equilibrium position. AMPLITUDE: The maximum displacement from the equilibrium position FREQUENCY: The number of oscillations completed in a second (hertz) PERIOD: The time taken for an oscillation. f=1/T; T=1/f WAVELENGTH: The distance between consecutive points on the wave which are in step (ie in phase) WAVE SPEED: The speed of travel of the energy of the wave. INTENSITY: The rate of flow of energy through unit area perpendicular to the direction of travel of a wave. Unit: Wm-2 Students should know that intensity ∝ amplitude 2.

Draw and explain displacement–time graphs and displacement–position graphs for transverse and for longitudinal waves.







Derive and apply the relationship between wave speed, wavelength and frequency.
 * 1) There are f waves in one second
 * 2) Each wave is lamda metres long
 * 3) In one second, the distance travelled is f times lamda



State that all electromagnetic waves travel with the same speed in free space, and recall the orders of magnitude of the wavelengths of the principal radiations in the electromagnetic spectrum.