Physics Mind Map

Physics Mind Map

1. AS

   • Particles
   • Mechanics
   • Waves
     • Progressive Waves
       • Carries energy from one place to another without transferring material
       • Reflection - the wave is bounced back when it hits a boundary
       • Refraction - the wave changes direction as it enters different medium
       • Wave Speed = Distance travelled/Time taken
         • Speed of wave = Wavelength x frequency
         • Frequency = 1/Period
           • F = 1/T
     • Transverse Waves
       • Vibrate at right angles to the direction of energy transfer
       • Electromagnetic waves
         • Travel through magnetic and electric fields
     • Longitudinal Waves
       • Vibrate along the direction of energy transfer
       • Most common longitudinal wave is Sound
     • Polarised Waves
       • Polarisation can only happen for transverse waves
         • Evidence that electromagnetic waves are transverse
       • Only oscillate in one direction
       • Ordinary light waves are a mixture of different directions of vibration
         • They can be polarised using a polarising filter
           • If you have two polarising filters at right angles, then no light will get through
             • Light become partially polarised when reflected from some surfaces
               • Examples of polarised waves are TV and Radio signals
     • Superposition
       • When two or more waves pass through each other
       • When the waves cross, the displacements of each wave combine
       • Interference
         • Constructive - crest + crest = bigger crest
         • Destructive - Crest + Trough = nothing (cancel out)
         • To get an interference pattern - two sources must be coherent
         • Coherence - same wavelength, frequency and a fixed phase difference between them
       • Phase
         • In phase means they are both at the same point in the wave cycle
           • Points in phase have the same displacement and velocity
         • In Phase - Two points with a phase difference of 0 or 360 are in phase
           • Points with phase differences of odd number multiples of 180 are exactly out of phase
     • Stationary Waves
       • The superposition of two progressive waves with the same frequency (wavelength), moving in opposite directions
       • No energy is transmitted
       • Each particle vibrates at right angles
         • Nodes are where the amplitude of the vibration is 0
         • Antinodes are points of maximum amplitude
       • First Harmonic - The Stationary wave is vibrating at the lowest possible resonant frequency
         • It has one 'loop' with at node at each end
           • Second Harmonic - Twice the frequency of the first harmonic. There are two 'loops' with a node in the middle, and one at each end
             • Third Harmonic - Thee times the frequency of first harmonic. 1.5 wavelengths fit.
   • Circuits
   • Materials
   • Quantum

2. A2

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