AS Physic Unit 2 Waves

HideShow resource information
View mindmap
  • Waves
    • The nature of waves
      • Progressive wave
        • A pattern of disturbances travelling through a medium and carrying energy with it.
        • It involves the particles of the medium oscillating about equilibrium position.
        • It does not involve the transfer of matter.
      • Transverse Waves
        • Particle oscillations are at right angles to the direction of travel of the wave.
        • Example of a transverse waves is light.
      • Longitudinal waves
        • The particles oscillations are parallel to the direction of travel of the wave.
        • An example of a longitudinal wave is a sound waves.
      • Displacement - distance graph is a snapshot of the wave at a particular time.
      • A displacement-time graph follows the movement of one particle over a given time.
      • Characteristic
        • Wavelength
          • the minimum distance between two points on the wave oscillating in phase.
        • Frequency
          • the number of cycles of a wave that pass a given point in one second
        • Amplitude
          • distance from the middle of the wave to the crest
        • Speed
          • the distance traveled by the wave one second
      • Phase
        • The relationship between the pattern of vibration of two points on a wave.
        • Points oscillating in phase  will be multipliers of 360
        • Points oscillating in anti phase will be 180  out of phase.
      • Wave Equation
        • Speed = frequency x wavelength
          • Speed is in ms                   Frequency is in Hz               Wavelength is in m
      • Polarization
        • A transverse wave in which the particle oscillations occur in only one of the directions at right angles to wave propagation.
        • If you try to view polarized light through a second polarizer filter rotating 360  the what you would see would be alternating light and dark.
    • Wave poperties
      • Reflection
        • As the waves strike a plane barrier they are reflected. This is very similar to a beam of light reflecting on a plane mirror.
        • If a cruve barrier is used, the waves can be made to converge at a point. the angle of incidence is equal to the angle of reflection.
      • Refraction
        • the change in direction of a wave at a boundary between two materials. This is caused by the change in speed.
      • Diffraction
        • The spreading out of a wave when it meets an obstacle into regions where it would not be seen if it moved only in straight lines.
      • principle of Superposition
        • If the waves from two sources occupy the same region then the total displacement at a point is the vector sum of the displacements of the individual waves at that point.
        • there are two types of interference when this takes place. Constructive and Destructive interference.
          • Constructive Interference - if two waves arrive at a point in phase, have the same frequency and equal amplitude.
          • destructive Interference - if the peak of one wave arrive at the same time as the toughs fro the other. There will be a smaller amplitude and sometimes cancel out
        • Coherence
          • There is a constant phase difference and same frequency.
          • An example is a laser light.
      • Path Difference
        • A measure of the distance between two waves arriving at a point in terms of their wavelength.
        • If we consider the effect of superposition at many points, an interference pattern will develop showing areas with constructive and destructive interference.
        • if the path difference is S2P - S1P equals a whole number of wavelengths then the waves arriving at point P in phase will produce constructive interference
        • If S2P - S1P is equal to multipliers of half wavelengths then waves arriving in anti-phase at point P will produce destructive interference.
      • Young's Double Slit Experiment
        • Two light sources at the double slits are produce. Because these two light sources originate from the same primary source, they are coherent and create an interference pattern.
        • Bright fringes can be created when the diffracted waves overlap and are caused by constructive interference.
        • Dark fringes can also be created from destructive interference.
      • The diffraction grating
        • Its a plate on which there are a very large number of parallel, identical and closely spaced slits.
        • If monochromatic light is incident n this plate, a pattern of narrow bright fringes are produces.
        • As there are many slits, the bright fringes are extremely narrow, and usually much further apart than the double slit experiment.
        • dsin0 = n
          • d = slit width n= order        number           = wavelength 0 = angle
          • A very small d makes the orders much further apart and a large number of slits makes the beams much brights and sharper.
        • With white light
          • Each wavelength making up the white light is diffracted differently. Red is diffracted the most and violet is diffracted the least.

Comments

No comments have yet been made

Similar Physics resources:

See all Physics resources »See all Waves resources »