Waves Flashcards
Define transverse waves.
Transverse waves are waves where the vibrations are perpendicular to the transfer of energy.
Define longitudinal waves.
A longitudinal wave is a wave where the vibration is parallel to the transfer of energy.
How is the plane of polarisation of an electromagnetic wave define?
It is the plane in which the electric field oscillates.
What is polarisation?
Polarisation the process by which the waves of light or other electromagnetic radiation are restricted to certain directions of vibration.
What is the displacement of a vibrating particle?
It’s distance and direction from its equilibrium position.
Define the amplitude of a wave.
The amplitude is the maximum displacement of a vibrating particle. For a transverse wave this is the height of a peak or depth of a trough.
Define wavelength.
The distance between two crests of a wave.
What is one complete cycle of a wave?
This is from maximum displacement to the next occurrence of maximum displacement.
What is the period of a wave?
This is the amount of time for one complete wave to pass a fixed point.
Define phase difference between two vibrating particles.
The phase difference between two vibrating particles is the fraction of a cycle between the vibrations of the two particles, measured either in degrees or radians, where 1 cycle = 360° = 2π radians. For two points at distance ‘d’ apart along a wave of wavelength ‘λ’, the phase difference in radians = 2πd/λ.
What is the principle of superposition?
The principle of superposition states that when two waves meet, the total displacement at a point is equal to the sum of the individual displacements at that point.
Define coherency.
Waves are coherent when they have a constant phase relationship.
What causes standing or stationary waves?
Two progressive waves in phase moving in opposite directions.
What causes constructive interference?
A peak and a peak or a trough and a trough.
What do waves have to be to interfere?
In a constant phase relationship.
