Waves Flashcards
(18 cards)
Wavelength
Wavelength - distance from one peak to the next
Frequency
How many complete waves there are per second
Amplitude
Height of a wave
Period of a wave 😂😂
Time taken for one complete wave to pass a point
F=1/T
Wave speed equation
Speed = frequency x wavelength
Transverse waves
Vibrations are 90 degrees to the direction of the energy
Eg light, EM waves, waves on strings, ripples on water, a slinky wiggled up and down
Longitudinal waves
The vibrations are along the same direction of energy transferred
Eg sound and ultrasound, shock waves and a slinky if you push it at the end
Waves all transfer…
Information without transferring matter
7 different EM waves
Smallest wavelength and largest frequency
Radio waves Micro waves Infra red Visible light Ultra violet X rays Gamma rays
Largest wavelength and smallest frequency
Uses of EM waves
Radio waves- communication tv and radio
Microwaves - heating food and satellite communication
Infrared - heating and monitor temp
Light signals can travel through optical fibres(used in medical or broadband internet wires)
More uses of EM waves
Visible light - photography
Ultraviolet- fluorescent lamps
X rays - see inside things. Human body
Gamma radiation - sterilising medical equipment or food
Dangers of EM waves
Higher frequency EM Radiation is more dangerous
Microwaves - can heat human body tissue
Infrared - burns skin
UV -cause blindness and damage surface cells
Gamma - cause cell mutation, tissue damage or cancer
Reflection of light
Angle of incidence = angle of reflection
Wave refraction
When a wave crosses into a different substance is changes speed
If the wave hits the denser boundary face on it slows but carries on in the same direction
But if a wave meets a different medium at an angle the first bit of the wave slows down and the wave changes direction, refracted.
Refractive index (n) =
Speed or light in vacuum/ speed of light in material
Snells law
N = sin(i)/ sin(r)
Snell’s law for critical angles
Sin C = 1/n
Sound waves
Loudness increases with amplitude
The higher the frequency, the higher the pitch
