Waves Flashcards
Transverse waves
The medium moves at right angles to the direction of the motion of the wave
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Diffraction
The spreading of waves as they pass by edges of an obstacle
Sound waves bend round corners
Longitudinal waves
The medium moves in the same direction as the motion of the wave
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Wavelength
Top of wave to top of wave
Period of wave
Wave crosses the black line to same part of wave crosses the black line / Time taken for the source to produce one wave
Amplitude (wave)
Black line to the top of the wave
Analogue electrical signals
Continuously variable voltages
Digital electrical signals
Only have values of 0 and 1 in the binary number system
Advantages of digital (4)
Digital doesn’t pick up interference
Eliminates unwanted noise
Much more information can be conveyed this way
Cleaner
Sound (3)
Longitudinal wave
Can’t travel through a vacuum
Can: reflect(echoe), refract, diffract
Amplitude (sound)
Loudness
Pitch
Effected by frequency
Total internal reflection
Happens when travelling through a more optically dense material into a lesser one
Slow speed to quick
Refraction of light
Te bending of light happens when travelling through differ materials
Refraction- into glass
Bent towards the normal
Refraction- out of glass
Bent away from the normal
Incident ray
Light beam entering glass
Refractive ray
Light beam just in glass
Electromagnetic spectrum
Increasing frequency-decreasing wavelength
Radio waves Microwaves Infrared Visible light Ultraviolet X-rays Gamma rays
Colours of the electromagnetic spectrum
Red Orange Yellow green Blue Indigo Vicolet
Light waves
Angle of incidence = Angle of reflection
Transverse
90* normal hitting the mirror
Electromagnetic waves
Are transverse
Do not use a material medium to Travel
Speed of electromagnetic waves
Through a vacuum 300,000,000 m/s
Uses of radio waves
Communication of information
Problems of x-rays
Cell mutation and cancer
X-rays
To examine bones
Uses of Microwaves
Heating food,satellite communication and radar
Problems of microwaves
Can directly heat internal body tissue
Uses of Infrared
Heating devices, night vision cameras
Dangers of infrared
Absorbed by our skin, results in burns
Visible light
Photography, optic fibres
Uses of ultraviolet
Fluorescent lamps, sterilising water
Emitted by the sun
Problems of ultraviolet
Skin cancer, damage to the eyes
