waves Flashcards
What are progressive waves
carries energy from one place to another without transferring any material
What is displacement
how far a wave has moved from its un-disturbed position, measured in metres
What is amplitude
The maximum displacement between the undisturbed position to the crest or trough of a wave.
What is wavelength
Measured in metres it is the length of one full wave cycle. (distance from tow peaks/troughs)
What is the period
Time taken for one whole wave cycle, measured in seconds
What is the frequency
the number of whole wave cycles per second passing a single point , measured in HZ
What is phase and phase difference
phase is the measurement of the position of a certain point along a wave cycle, while phase difference is the amount by which one wave lags behind another wave
What is a transverse wave
The displacement of the particles are at right angles to the direction of energy transfer. All electromagnetic waves are transverse
What is a longitudinal wave
The displacement of the particles is parallel to the energy transfer, e.g. sound waves
What are polarised waves
Waves that travel in only one direction, examples of this being used are polarised filters e,g. one way sunglasses
How does light change as it travels from air into glass
- Wavelength decreases
- Frequency stays same
- Speed decreases
How does total internal reflection work in an optical fibre
- An optical fibre is a very thin flexible tube of glass that can carry signals over a long distance
-Core - high refractive index
-Cladding -low refractive index
this allows total internal reflection and prevents light being lost
The cladding also acts as good protection
-Light at incident greater than the critical angle
How does a single slit before the double slit help with looking at light diffraction
single slit acts as a point where the light can become coherent- path length between single slit and double slit are the same
How would the pattern from double slit experiment change when violet laser is replaced with green laser
green laser has a larger wavelength so would the spacing would be larger apart
What is the equation for path difference
pathdifference = 2λ
