BRAINCAKEOptics
Revision notes for Optics in AQA Physics (7407). Read the start of any lesson here, then sign in free for the whole lesson, the R.E.C.I.P.E. recall steps and the quiz.
- Refraction of LightWhen a light ray is incident at a boundary, the normal is an imaginary line perpendicular to the boundary Refraction is the change of direction that…
- The Refractive IndexThe relationship between the amount of refraction and the materials the light is passing through is given by Snell's Law.
- Refraction from Air to Glass and Glass to AirThere is a reciprocal relationship between the refractive indices from air to glass and glass to air. airnglass = 1 glassnair Light is refracted…
- Refraction by a Trianglar PrismDifferent wavelengths refract to different extents so white light will split into its constituent colours when refracted by a triangular prism.
- Explaining RefractionThe speed of light is different in each substance.
- Refraction at a BoundaryRefraction occurs at the boundary between two transparent substances.
- White LightA prism can be used to split a beam of white light into colours of the spectrum.
- Total Internal ReflectionWhen light travels from glass to air it refracts away from the normal.
- DiamondsA diamond splits white light into colours of the spectrum when light passes through it. ndiamond = 2.417 so there is more dispersion critical angle…
- Optical FibresOptical fibres are made of a core of transparent material surrounded by a layer of cladding of a lower refractive index to reduce light loss from…
- Material(Spectral) DispersionThe speed of light in a medium depends on its wavelength.
- Modal (Multipath) DispersionTotal internal reflection occurs at the core-cladding boundary.
- Medical EndoscopeMedical endoscopes make use of total internal reflection.
- Young's Double SlitThere were two competing theories about light: the wave theory and the particle theory.
- The Double Slit EquationThe fringes are formed due to interference of light from the two slits.
- CoherenceCoherent waves have the same frequency and a constant phase difference.
- Wavelength and InterferenceThere are alternate light and dark fringes on the screen.
- White Light FringesSince fringe separation depends on wavelength and different colours have different wavelengths the fringes of different colours can be seen.
- LasersLASER stands for Light Amplification by Stimulated Emission of Radiation.
- DiffractionDiffraction is a property of all waves.
- Diffraction of Water WavesDiffraction of water waves increases if the gap is narrower or the wavelength is longer.
- Single Slit DiffractionWith the double slit experiment, if the slits are too far apart or too wide, light from the slits does not overlap ad no interference pattern is…
- Young's FringesThe intensity is greatest at the centre of the central fringe.
- Explaining Single Slit Diffractionfringe spacing w = λD s slit separation width of central fringe W = 2λD a slit aperture width Wavelets emitted simultaneously at point sources…
- Diffraction GratingA diffraction grating is a plate with closely spaced parallel slits ruled on it.
- More on the Diffraction Grating Equationdsinθ = nλ The wavefront emerging from P reinforces the wavefront formed from Q in earlier cycles.
- Types of SpectraDiffraction gratings a made by etching parallel lines very close together on a smooth glass plate.