Physics- Waves Flashcards
Speed (wavelength)
V = f x wavelength
Frequency
F = 1/T
Refractive index
n = sin i/sin r
Critical angle
Sin C = 1/n
Light and electromagnetic waves are ???
TRANSVERSE WAVES
Examples of TRANSVERSE WAVES
Light
EM waves
Slinky spring wiggled up and down
Ripples on water
Sound waves are ???
LONGITUDINAL WAVES
Examples of LONGITUDINAL WAVES
Sound
Shock waves
Slinky spring pushed on one end
In transverse waves the vibrations are……
90 degrees to the direction of energy
Longitudinal waves the vibrations are…..
Along the same direction as energy is transferred
EM Waves longest wavelength to shortest wavelength
Which has highest / lowest frequency???
Radio waves, microwaves, infra red, visible light, ultra violet, x Rays, gamma rays
VISIBLE LIGHT shortest wavelength colour??
Longest wavelength colour??
Frequency?
RED has longest wavelength, lowest frequency
VIOLET has shortest wavelength, highest frequency
Uses of RADIOWAVES
Communications
Radio broadcasting
Uses of MICROWAVES
Satellite communication
Cooking - microwaves absorbed by water molecules in food
Uses of INFRARED
Heating
Monitor temperature
Uses of VISIBLE LIGHT
Can travel through optical fibres - used for telephone and broadband internet cables
Photography
Uses of ULTRAVIOLET
Fluorescent lamps
Uses of X-RAYS
See inside things - internal structure of objects
Uses of GAMMA RAYS
Sterilising medical equipment
Sterilising food
Danger of MICROWAVES and protection?
Can heat human body tissue
Needs shielding to prevent from reaching user
Danger of INFRARED and protection?
Too much infrared exposed to skin- skin burning
Wear insulating materials to reduce amt reaching skin
Danger of ULTRAVIOLET and protection?
Damage surface cells
Blindness
Cell mutation or destruction and cancer
Wear sunscreen
Stay out of strong sunlight
Danger of GAMMA and protection?
(Highest frequency so most harmful - carry most energy)
Cause cell mutation and destruction -> tissue damage or cancer
Exposed for short time only, sources kept in lead-lined boxes
Law of reflection ?
Angle of incidence = angle of reflection
