Flashcards
Topic 6 - Waves
Cards in this deck (27)
- 1waves- transfer energy in the direction they are travelling
- when waves travel through medium, the particles of the medium oscillate and transfers energy between each other
- BUT overall, the particles stay in the same place ONLY energy is transferred - 2what is amplitudethe maximum displacement of a point on the wave from its undisturbed position
- 3wavelengththe distance between the same point on two adjacent waves
- 4frequencythe number of complete waves passing a certain point per second
it is measured if Hertz ( 1 Hz is 1 waver per seconds) - 5period of a wave calculationperiod (s) = 1 / frequency (Hz)
T = 1 / f - 6transverse waves- in transfers waves the oscillations (vibrations) are perpendicular ( at 90 degrees) to the direction of energy transfer
- the vibrations are sideways - 7examples of transverse waves- electromagnetic waves (light)
- ripples and waves in water
- a wave on a string - 8longitudinal waves- in longitudinal waves the oscillations are parallel too the direction of energy transferred
- 9examples of longitudinal waves-sound waves in air (ultrasound)
- shock waves (some seismic waves) - 10wave speed calculationwave speed (m/s) = frequency (f) x wavelength
- 11the continuous spectrum of EM waves- all EM waves are transverse waves that transfer energy from a source to an absorber
- all EM waves travel at the same speed through air or a vacuum (space)
- electromagnetic waves from a continuous spectrum over a range of frequencies. so there are different types - 12types of EM waves- radio waves
- micro waves
- infrared waves
- visible light rays
- ultra violet waves
- x rays
- gamma rays - 13what is refraction?- waves changing direction at a boundary
- when a wave crosses a boundary between materials at an angle it changes direction
- the amount refracted depends on how much the waves speed up/down. this depends on the density (thicker material slows it down) - 14radio waves- alternating currents aren made up of oscillating charges. As the charges oscillate they produce oscillating electric and magnetic fields
- you can produce radio waves using an alternating current in an electrical circuit
- when radio waves reach a receiver they are absorbed
-the energy carried out by the waves is transferred to the electrons in the material of the receiver
- this energy causes the electrons to oscillate and, if the receiver is part of a complete electrical circuit, but generates an alternating current
- this current has the same frequency ads the waves that produced it - 15How are radio waves usedfor communication
- 16EM waves: Microwaves and satellitesthey are used by satellites:
communication between satellites uses microwaves in order to pass through the earth atmosphere - 17EM waves: Microwaves and ovens- in microwave ovens that need to absorb watery molecules in food causing it to heat up
- the water molecules then transfer this energy to the rest of the molecules in the food by heating - 18EM waves: Infrared radiationinfrared cameras can detect infrared radiation and monitor temperature
- the camera detects IR radiation and turns it into an electrical signal. - 19EM waves: Fibre Optic Cables- optical fibres are thin glass or plastic fibres that can carry data over long distances via pulses of visible light
- they work because of reflection the light rays are bounced until they reach the end of the fibre - 20EM waves: X-rays and Gamma raysthey are used in medicine
- xrays pass easily through flesh but not bone so the radiation absorbed gives you a picture - 21EM waves: some can harmful- low frequency waves like radio waves don't transfers that much energy so to can pass through tissue without being absorbed
- High frequency waves like UV waves all transfers lots of energy so can cause lots of damage - 22risks can be different for different parts of the bodyhead = 2.0 radiation dose
chest = 8.0 radiation dose - 23objects absorb and emit infrared radiation-all objects continuously emit and absorb radiation
- the hotter the object, the more infrared radiation it gives out
- an object thats hotter than its surroundings emits more IR radiation than it absorbs - 24wave equationfrequency x wave length
- 25the law of reflectionthe angle of incidence is ALLWAYS equal to the angle of reflection
- 26what is refractionwhen light changes direction as it goes from one medium to another
- 27Electromagnetic Spectrum: high frequency short wavelength high energy most penetratingGamma
X Rays
Ultra - violet
Light
Infared
micro waves
Radio
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- GCSE Physics Flashcards on Topic 6 - Waves , created by seren .nml on 21/04/2021.
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