C.3 Wave Phenomena Flashcards
What two things happen at the boundary when waves travel from one medium to another?
Some of the wave’s energy is reflected, some is refracted
Refraction
When a wave enters a new medium and changes speed
Transmissiom
Passage of the wave through the medium
When will a wave move towards normal in new medium?
When it is slowing down
When will a wave move away from normal in new medium?
When it is speeding up
Refractive index (n)
Measure of how fast a way travels in a medium
When does total internal reflection occur?
When light is travelling from a more to less optically dense medium, when the angle of incidence is greater than the critical angle
How to work out critical angle
sin 0c = 1 / n1
Wavefront
Line connecting points along a wave with the same phase/displacement
Ray
Line drawn to show direction a wave is travelling when viewed from above
Diffraction
When waves move past an obstacle or through a gap and the waves spread out
If gap width = wavelength
Circular wavelengths are produced
Why does amplitude decrease in diffraction?
Energy is spread out over a larger wavefront
Constructive interference
When waves meet in phase and form a resultant wave with amplitude equal to the sum of the two individual waves
Destructive interference
When waves meet 180* out of phase, they will cancel each other to give a wave amplitude of 0.
Principle of superposition
If two or more waves meet, the resultant displacement at any point is found by adding the displacements produced by each individual wave
Geometry of the interference pattern depends on…
Wavelength (λ), distance between double slits (d) and distance from double slits to interference pattern (D)
