11.5 +11.6 Electromagnetic Waves, Intensity Flashcards
Define electro magnetic waves
Waves that travel by oscillations of the electromagnetic field. Always transverse waves
What is the electro magnetic spectrum and the corresponding wavelengths ?
725233 starting at 10^6
What is the order of visible light
ROYGBIV
Richard of York gave battle in vain
Red, orange, yellow, green, blue, indigo, violet
what is the plane of polarisation of an EM wave?
the plane in which the electric field vibrates
what is intensity + formula ?
the power per unit area
how does intensity vary with distance?
waves (from a point source spread out as they travel outwards)
* intensity falls as power is spread over an increasing area
what is the area over which the power is spread out by?
surface area of a sphere:
* radius = distance travelled from the source
what is the formula for intensity (with distance)?
inverse square relationship between intensity and distance
what is the relationship between intensity and amplitude?
intensity is directly proportional to the amplitude squared
In what scenario do all EM waves travel at the same speed?
a vacuum
what phenomona can all waves experience?
- reflection
- refraction
- diffraction
- superposition
polarisation only for EM
what is the wavelength for radio waves?
what is the typical wavelength range for micro waves?
what is the typical wavelength range for infra red waves?
what is the typical wavelength range for visible light?
what is the typical wavelength range for UV ?
what is the typical wavelength range for X rays?
what is the typical wavelength range for Gamma rays?
