AS Physics - Unit 2 Revision cards for Unit 2. 4.0 / 5HideShow resource informationPhysicsASAll boardsCreated by: Mike JonesCreated on: 13-01-12 14:48 Nature of Waves Waves transfer energy away from its source Progressive (moving) waves carrier energy from one place to another without transferring any material. Electromagnetic waves cause things to heat up X-rays and gama rays knock electrons out of their orbits, causing ionisation Loud sound make things vibrate Wave power can be used to generate electricity Since waves carry energy away, the source of the wave loses energy 1 of 3 Waves Displacement, X, (in meters) - how far a point on a wave has moved from its undisturbed position Amplitude, a, (in meters) - maximum displacement Wavelength, λ, (in meters) - the length of one whole wave, from crest to crest or trough to trough. Period, T, (in seconds) - time taken for a whole vibration Frquenc, f, (in Hertz) - number of vibrations per second passing over a given point Phase difference (measured in degrees or radians) - amount of which one wave lags behind another. 2 of 3 Reflection and Refraction and Frequency Reflection and Refraction Reflection - wave bounces back when it hits the boundary. Refraction - wave changes direction as it enters a different medium. Frequency - inverse of the time period Frequency = 1 / period Units 1Hz = 1s-1 3 of 3
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