# Physics topic 4

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• Created by: molly
• Created on: 01-04-18 21:31
• Physics-T4
• Waves
• Longitudinal waves: A wave where the vibrations are parallel to the direction in wich the wave is travelling. E.g sound waves and seismic P waves
• Transverse waves: A wave where the vibrations are at a right angle in wich the wave is travelling. E.g water, electromagentic
• describing waves
• Frequency: number of waves passing a point each second (Hz)
• Speed: the speed (m/s)
• period: length of time it takes one wave to pass a given point
• wavelength: distance from one point on a wave to the same point on the next wave (M)
• Amplitude: maximum point on a wave from its resting position (M)
• Velocity: speed in the direction its travelling
• Wave equations (on flash cards)
• Refraction
• refraction can result in a change in direction when a wave enters a different medium
• Waves crossing boudries
• when wave reach an interface they can be:
• reflected - bounces off
• Refracted - the wave passes into a new material but changes direction
• Transmitted - wave passes through the material
• Absorbed - the wave disappears as the energy it is carrying is transferred into the material
• Ears and Hearing
• see notes
• Ultrasound
• higher than 20000 Hz
• Infrasound
• Lower than 20 Hz
• Longitudinal P waves
• Transverse S waves