Waves Flashcards
What is a progressive wave?
A wave that transports energy without transporting material (and is made up of particles of a medium oscillating.
Define amplitude.
The maximum displacement from the equilibrium position.
Define frequency.
The number of COMPLETE oscillations passing through a point per second.
Define wavelength.
The length of one complete oscillation.
Define period.
The time taken to complete one full oscillation
Define phase and suggest its units.
The position of a certain point on a wave cycle. Its units are radians, degrees, or fraction of a wave cycle.
Define phase difference.
The cycle difference between two waves at the same point
What is a transverse wave?
The oscillation of particles is perpendicular to the direction of energy transfer.
What is a longitudinal wave?
The oscillation of particles is parallel to the direction of energy transfer.
What type of waves are electromagnetic waves?
Transverse (waves)
Define node.
A position of zero displacement in a stationary wave.
Define antinode.
A position of maximum displacement in a stationary wave.
What are coherent waves?
Waves that have the same frequency, same wavelength, and have a constant phase difference.
What is wave speed?
The distance travelled by a wave per second.
Which wave type can be polarised?
Transverse.
What is superposition?
The adding together of wave displacements that occurs when two separate sources overlap. The displacements add mathematically.
Define constructive interference.
When two waves in phase and travelling in the same direction interfere, adding their amplitudes.
Define destructive interference.
When two waves in antiphase (180 degrees out of phase) interact and cancel each other out.
Define stationary wave.
A wave that stores energy instead of transferring it.
What is the fundamental frequency/first harmonic?
The lowest frequency for a standing wave to form.
Define diffraction.
The spreading out of waves when they pass through a small gap OR around an obstacle.
What type of light will displays an interference pattern?
Monochromatic light.
Define refraction.
When a wave changes speed when it enters a new medium.
If a wave enters a medium more optically dense, what happens to the wave?
The wave slows down and bends towards the normal.
If a wave enters a medium less optically dense, what happens to the wave?
The wave speeds up and bends away from the normal.
What is the critical angle?
The angle of incidence when total internal reflection occurs( angle of refraction is 90 degrees to the normal)
What is optical fibre?
A thin glass fibre through which signals are passed through.
What are the two main parts of step-index optical fibres?
- A core made from a high-refractive index material.
- Cladding made from a low-refractive index material.
What are the two components of electromagnetic waves?
Magnetic and electric oscillations that are perpendicular to each other.
Define polarisation.
The restriction of a wave so that it can only oscillate in one direction.
What conditions are needed for a stationary wave to be produced?
The waves need be travelling in opposite directions, and have the same frequency, wavelength, and amplitude.
