# Physics AQA Unit 2 - Waves

A quick mindmap for those struggling with wave properties

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• Created by: zach
• Created on: 20-03-13 16:05
• WAVES
• Reflection
• Straight waves directed at acertain angle to a hard flat surface reflect off at the same angle.
• Refraction
• Occurs when waves pass into different material changing the wave speed
• The direction of motion is also changed.
• Also changes wavelength
• Also changes wavelength
• Diffraction
• A wave is passed through a tiny gap
• The narrower the gap, the more the waves spread out.
• The longer the wavelength, the more the waves spread out.
• Types of Waves
• Longitudinal
• When the direction of virbation is parallel to the direction of the wave.
• E.g. Sound Waves
• Transverse
• When the direction of the vibration is perpendicular to the direction of the wave.
• E.g. Electromagnetic Waves
• Polarisation
• Transverse waves are plane-polarised, if they stick to one plane.
• Longitudinal can not be ploarised as they switch from plane to pane leaving them unpolarised.
• Masuring Waves
• Key Terms
• Displacement
• Distance and direction from a particles orgianl position
• Amplitude
• Maximum displacement of a vibrating particle.
• Wavelength
• Distance between two peaks
• One complete cycle
• From one peak to the next
• Period
• Time for one complete wave to pass a fixed point
• Frequency
• The number of cycles per second (hertz)
• Wave speed
• c = f λ
• Phase Difference
• cycle=360 deg =2π
• Phase dif = 2πd / λ
• Superposition
• When two waves meet, the toatal displacement at a point is equal to the sum of the individual displacements at that point.
• Where a crest meets a crest, a supercrest is created, the two waves reinforce each other.
• Where a trough meets a trough, a supertrough is created, reinforcing one another.