3.0 Waves Flashcards
What is a wave
The propagation of a quantity through the oscillation of a medium
Define phase
The position a point is along the cycle of a given wave
Define phase difference
The relative difference in phase between two points on a wave or two waves
Medium of longitudinal waves
Can propagate through any solid, liquid or gas
Medium of transverse waves
Can propagate through solids, some liquids and electromagnetic media
Define polarisation
The process where waves are restricted to oscillate in a specific direction or plane
Describe how polarisation provides evidence for the nature of transverse waves
Polarisation restricts oscillation in the perpendicular direction. Only transverse waves can be polarised. So transverse wave oscillate perpendicularly
What are stationary waves
Waves that oscillate but don’t pass through a medium
Formation of a stationary wave
Formed from the superposition of two coplanar waves with equal wavelengths and magnitudes traveling opposing directions.
Formation of a node
Waves are in constant antiphase, destructive interference occurs, resulting in point of minimum amplitude
Formation of an antinode
constructive interference occurs, resulting in point of maximum amplitude
Formation of stationary waves on a string
Oscillator created wave on string which reflects at a fixed point. two waves superpose forming stationary wave with node at fixed point
Sources of monochromatic light
Lasers, filters
Youngs double slit experiment
The use of two coherent sources or the use of a single source with double slits to produce an interference pattern.
Problems with double slit formula
assumes small angle approximation so reduces accuracy
Describe an interference pattern
Equally spaced bright fringes separated by dark fringes, with reducing intensity from the center. Symmetrical on both sides
Describe an interference pattern with white light
central maxima of white light with outer fringes of spectrums, with red on the outside and blue on the inside
what are some safety issues with lasers
Danger to eyes - wear goggles
Hard to notice - signpost
how has knowledge progressed
New experiments have allowed us to understand the nature of electromagnetic waves
Describe a diffraction pattern
Central maxima of double width with repeating dark minima and bright maxima of reducing intensity from center. Symmetrical on both sides
Describe a diffraction pattern with white light
A central maxima of white light with outer maxima being spectra, with red on the outside and green on the inside
Applications of diffraction gratings
spectrometry, fiber optics, telecommunications, astronomy
define refraction
The apparent bending of light when passing through a boundary from one medium to another
