# AS Physics - Waves

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• Types of Wave
• Transverse
• The disturbance in the wave is perpendicular to the direction the wave is travelling.
• All waves on the EM spectrum are transverse.
• Other examples include ripples on water and waves on ropes.
• Can be shown as displacement distance graphs or displacement time graphs.
• Longitudinal
• Disturbances take place parallel to the direction in which the wave travels. (The Propagation.)
• Most common type are sound waves. Consisting of compressions and rarefactions. e.g ||| | | | ||| | | |
• Aren't normally plotted, but if they are then displacement time graphs.
• Sound waves - a vibrating surface in contact with air.
• Polarised
• Only oscillates in one direction.
• Can only happen for transverse waves.
• Mechanical
• Pass through a material and are vibrations of said material.
• E.g: sound waves, seismic waves, strings.
• Electromagnetic
• Vibrating electrical or magnetic fields through space. (No material needed.)
• E.g: EM spectrum.
• Seismic
• Can be longitudinal or transverse.
• In an earthquake  the majority of the energy is transferred as wave energy and is transmitted over long distances.
• Waves
• Interference
• Definition
• The way two or more waves affect each other when they meet.
• When two or more waves meet, the total displacement is the sum of the individual displacement that any given wave would cause at that point.
• Constructive
• When the crests of any two waves coincide, the create an amplified wave.
• Both waves are in phase with each other.
• Destructive
• When the crests of two waves are different, they create a smaller wave.
• Waves are out of phase, half a cycle different from each other.
• Standing
• Have nodes where two waves cancel out so there is no movement.
• Anti-nodes where waves interfere and make height double wave. 2 anti-nodes equal wavelength.
• Waves
• Interference
• Definition
• The way two or more waves affect each other when they meet.
• When two or more waves meet, the total displacement is the sum of the individual displacement that any given wave would cause at that point.
• Constructive
• When the crests of any two waves coincide, the create an amplified wave.
• Both waves are in phase with each other.
• Destructive
• When the crests of two waves are different, they create a smaller wave.
• Waves are out of phase, half a cycle different from each other.