Waves Flashcards
(29 cards)
mechanical wave
A wave that passes through a substance - the particles in the substance vibrate due to wave and cause more vibrations
Electromagnetic wave
Oscillating electric and magnetic fields that progress through space without the need for a substance
Give examples of mechanical waves
Sound waves, seismic waves and waves on a string
Give examples of an electromagnetic wave
Radio waves, microwaves, infrared radiation, light, UV radiation, X - rays and gamma radiations
What is a longitudinal wave?
Waves with a direction of vibration parallel to the direction of propagation of the waves
Transverse waves
Waves in which the direction of vibration is perpendicular to the direction in which the wave travels
Examples of longitudinal waves
P-waves, sound waves
Examples of transverse waves
EM waves, S waves and waves on a string
Plane polarised wave meaning
Transverse waves that vibrate in one plane only
What is amplitude?
The maximum displacement of a particle in a wave from it equilibrium position
What is wavelength
The distance between the two points on successive oscillations of the wave that are in phase
What is time period
The time taken for one complete oscillation or cycle of a wave
What is frequency?
The number of complete oscillations per unit time
What is the speed of a wave?
The distance travelled by the wave per unit time
What is the wave equation that links speed, frequency and wavelength?
Speed = wavelength x frequency
For a wave of constant speed, as the wavelength increase what happens to the frequency?
Decreases
What is phase difference between to waves?
A measure of how much a point or a wave is in front or behind another
When a crest or trough of a wave is aligned, what can be said about them in terms of phase difference
No phase difference, the waves are in phase
When the crest of one wave aligns with the trough of another, what can be said about their phase difference?
Phase difference of pi, the waves are in antiphase
What is superposition?
The principle of superposition states that of waves from two sources (or travelling by different routed from the same source) occupy the same region then the total displacement at any one point is the vector sum of their individual displacements at that point
When are standing waves produced?
They are produced by the superposition of two waves of the same frequency and amplitude travelling in opposite directions
What do stationary waves do with energy?
They store it
What do progressive waves do?
Transfer energy
What is a node?
A regional where there is no vibration
