Waves And The Electromagnetic Spectrum Flashcards
(24 cards)
What do waves do
Transfer energy and information in the direction they are travelling
What happens when waves travel through a medium
The particles of the medium vibrate and transfer energy and information between each other but the overall particles stay in the same place
What is the amplitude of a wave
The displacement from the rest position to a crest or trough
What is the wavelength
The length of a full circle of the wave (eg. crest to crest)
What is the frequency
The number of complete cycles of the wave passing a certain point per second
What is the period of a wave
The number of seconds it takes for one full cycle
What are transverse waves
Waves where the vibrations are perpendicular to the direction the wave travels
What waves are transverse
All electromagnetic waves
S-waves
Ripples and waves in water
What are longitudinal waves
Waves where the vibrations are parallel to the direction the wave travels
What are examples of longitudinal waves
Sound waves
P-waves
What do longitudinal waves do
Squash up and stretch out the arrangement of particles in the medium they pass through making compressions and rarefactions
What are compressions
High pressure, lots of particles
What are rarefactions
Low pressure, fewer particles
What does the wave-speed tell you
How quickly a wave moves through space
What are the two ways to calculate wave speed
v = x
—
t
v = fy
What can happen when a wave meets a boundary between two materials
The wave is absorbed by the second material
The wave is transmitted through the second material
The wave is reflected
What happens when a wave is absorbed
The wave transfers energy to the materials energy stores
What happens when a wave is transmitted
The wave carries on travelling through the new material
What happens when a wave is reflected
The incoming ray is neither absorbed or transmitted but is instead ‘sent back’. This is how echoes are created
What is an example of when a wave is absorbed
Microwaves when energy is transferred to a thermal energy store, which leads to heating
What is an example of when a wave is transmitted
Lenses of glasses and cameras
What is an example of reflection of a wave
Echoes
What is refraction
When a wave hits a boundary at an angle, where this change of speed causes a change in direction
What are the electromagnetic waves
Radio waves Micro waves Infra red Visible light UV X rays Gamma rays
