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.
