Wave Behaviour and Electromagnetic Waves Flashcards
What are the three possible outcomes for when a wave meets a boundary between two materials?
1)the wave is absorbed by the second material: the wave transfers energy to the material’s energy stores (usually a thermal energy store) often leading to heating (e.g.microwave ovens).
2)the wave is transmitted through the second material: the wave continues traveling through the new material, often resulting in refraction (e.g. communication systems, lenses)
3)The wave is reflected : the incoming wave is sent back away from the second material, creating echoes.
*the outcome depends on wavelength and material properties.
What are electromagnetic (EM) waves?
Transverse waves that transfer energy from a source to an absorber.
What is the speed like of electromagnetic waves through air or a vacuum?
All EM waves travel at the same speed through air or a vacuum
How are EM waves able to travel through a vaccum (space)?
EM waves are vibrations of electric and magnetic fields (not of particles!!) allowing them to travel through a vacuum.
What is the wavelength for an EM wave usually like?
They vary in wavelength from around 10^-15 meters to more than 10^4 meters.
How are electromagnetic waves grouped?
They are grouped based on wavelength and frequency but they all merge to form a continuous spectrum
What is the order of the EM wave spectrum?
1)Radio Waves (rich)
2)Micro Waves (men)
3)Infra red (in)
4)visible light (Vegas)
5)Ultra Violet (use)
6)X-rays (eXpensive)
7)Gamma Rays (gadgets)
*they are ranked from the longest wave length (and lowest frequency) to shortest wave length (and highest frequency)
Why is there a large range of frequencies for electromagnetic (EM) waves?
-they are generated by various changes in atoms and their nuclei
-this also explains why atoms can absorb a range of frequencies- each one causes a different change
