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Module 7 Nature of Light - Coggle Diagram

- - - - Emission
        
        colored lines
        
        Discharge tubes
      - Continuous
        
        Full spectrum
        
        Sunlight and incandescent film
      - Absorption
        
        Black lines
        
        reflected sunlight
    - - Tempreture
        
        Black Body Curve- Graph Intensity and Wavelength
        
        Inversely proportional Temperature and Peak wavelength
        
        Wien's Law
        
        Peak wavelength = b/ Surface temperature
        
        b= 2.898 x 10^-3
      - Density
        
        Denser = Boarder spectrum lines
      - Rotational and Translation velocity
        
        Translational velocity can determined by doppler shift of spectra lines
        
        Red away larger wave lengths
        
        Rotational determined by the smear of spectral lines
      - Element composition
        
        Comparing Spectra of Planets with Spectra of Known elements
  - - - Gauss' law of E
        
        Explains how Electric fields permeate space
      - Gauss' Law of B
        
        How a magnetic field may permeate space
      - Faradays Law
        
        A change in electric field causes a change in magnetic field
      - Modified Ampere's Law
        
        How Magnetic field is produced from an I or E
    - - Spark gap experiment
  - - - Timed until he saw light on another hill was just testing reaction time.
    - - Timed eclipes of The Jupiter Moon Io
      - Noticed how eclipses were longer
        
        Estimated it took 22 minutes but didnt have distance
        
        later produced 2 x 10 ^ 8 m/s
    - - Turning cog that had light going through it and spun fast enough until light could not reflect back from mirror
      - 3.133 x ^8 m/s
    - - Turning mirror reflecting to another mirror, change in angle used to calculate time
      - 2.98 x 10^8 m/s
- - - - dsinO = m Lamda
        
        d distance between slits centre
        
        O is angle between straight to wall to maxima
        
        m is maxima number
        
        lambda is wavelength
      - Analysed how light moves around space
      - Observed results were patches high intensity light and then dark spots of no light
        
        Light patches were parts of constructive interference and dark patches deconstructive
  - - - Io intensity original
      - I is intensity seen past two polarisers
      - O is angle between two polarisers
    - - like fences for light
        
        if two polarisers of perpndicular polarisation are perpidicular no light go through
        
        But if a diagonal polarizer is in between some light get through fence
  - - - Small mass particles
      - Travel in rectilinear motion
      - Size of corpuscles indicates light big red small violet
      - perfectly elastic motion (Newtonian)
      - Explained
        
        refraction and reflection
        
        refraction as the particle was attracted to the gravity of the mass and thus changes course
        
        Reflection as it was perfectly elastic
      - Prism experiments concluding that particle size indicated color
    - - Light travels in wave fronts that ripple apart like in water
      - used Aether as medium
      - Explained
        
        Refraction and reflection as change in medium causes change in angle of wave fronts and the some are just reflected back outwards
        
        Diffraction explained as the wave front propagates it will produce wavelets that will bend with
        
        Evidince diffraction
- - - - BLack body graphs should have just gone exponentiolly up
        
        but they taper off past visible light
        
        Planck concludes that the higher frequency EM waves must require a even higher amount of energy that is really hard to occur
      - He comes up that a black body graph is not continuous but the the gaps are so small that it appears to be continuous
        
        Therefore EM waves must be in a quantised energy levels
        
        E = hf
  - - - It disagrees with wave model as the wave model predicts that by increasing the intensity of the EM wave that the electron would eject or that by leaving a wave emitting on the structure eventually it will project an electron
        
        but lower frequencies will never eject an electron and intensity does nothing if the frequency did not initally eject electrons
      - Increase I increase rate of emission but not K max
    - - Spark gap experiment
    - - Instantaneous as it does not require accumulation of energy from waves
    - - he observes the photo electric effect and how at certain frequencies no electrons are ever ejected
        
        concludes that the EM waves do not have high enough energy to dislodge the electrons
        
        and with Planck's quantized EM energy hypothesis he forms the photon model
        
        And that at certain frequencies there is a range of photons of diffirent energy levels with a max energy of E = hf for the photon
        
        So when the photon hits the MS the photon is absorbed by the electron and if there is enough energy pushes the photoelectron out of the MS
        
        Coming up with Kmax = hf - phi
        
        6 more items...
        
        Photon - Discrete energy packets
- - - - No Acceleration
        
        No net force acting on observer or frame of refernce
    - - Thought to be like a web or blanket that everything pushed through
        
        Fixed web therefore an absolute frame of reference
        
        Michelson and Morely Experiment
  - - - t = t0/(root)(1 -v^2/c^2)
        
        To is time measured by observer at rest relative to the event (proper time)
        
        T is dilated time ( bigger time
      - Speed of light is constant and all frame of referneces are equal
        
        So when two objects observe eachother time or movement it appears one is moving further in the same time and vice versa
        
        But as it is light as the distance appears longer the time must appear longer
      - Thought Experiment
        
        The train and mirror
      - When one frame of reference is moving at relativistic speeds (>0.1C) time will appear to slow down when outside of the inertial frame of refernece
    - - The laws of physics are the same in all frames of refernece
      - The speed of light in a vaccum is constant (c)
    - - l=lo(root)(1-v^2/c^2)
      - As A objct approaches the speed of light the length of the object along the axis of motion will appear shorter when observed outside of the frame of refernece along the object
    - - Muons have short half life and are made in atmosphere but are really fast like 0.9999C
        
        Therefore time of the muons travel dilates outside of its reference frame so that it
    - - Measure speed of two waves of light reflecting off perpendicular mirrors to measure the positioning of the ''aether''
        
        found that lengths travelled same therefore no true FOR therefore no aether and all equal
    - - Mass relieas on how an object is arranged and bonds it has
        
        mass extra = E/C^2
        
        Light massless but the energy possesses mass
        
        Mass is applicable to special relativity and as it approaches C the observed mass increases and thus heavier and require more energy to push and then denser creating loop making it require infinite energy to move a mass to C
      - Pv - MoV/Root1-v^2/C^2)
        
        v approach c P approach infinity
      - Conserved in all inertial frame of references