IGCSE›Oxford AQA IGCSE Physics›Mind mapsThe Electromagnetic SpectrumOxford AQA IGCSE Physics: Mind mapStudy pack PDFAlso for this subtopic:Revision notesFlashcardsSubtopic testCover factsWhat are EM waves?Transverse waves carrying energy from source to absorberNeed no medium - travel through a vacuumSame speed in a vacuum for all regionsForm a continuous spectrumThe orderRadio, microwave, infrared, visible, UV, X-ray, gammaFrequency and energy increase along the orderWavelength decreases along the orderWavelengths span about 10−1510^{-15}10−15 m to 10410^{4}104 mVisible and infraredVisible light is the only part the eye detectsRed has the longest wavelength, violet the shortestMatt black surfaces absorb and emit infrared bestShiny surfaces are good reflectorsHotter objects radiate more, at higher frequenciesEM spectrumradio to gammaRadioMicroIRVisUVUsesRadio: TV, radio, BluetoothMicrowaves: mobile phones, satellite TVInfrared: remote controls, night visionUV: security markingGamma: sterilising instruments and foodHazardsMicrowaves: heating of body tissueInfrared: skin burnsUV: skin cancer and blindnessGamma: genetic mutationsX-rays: absorbed by bone, pass through soft tissueExam tipsLearn the order exactlyMatch the specific hazard to the specific regionUV, X-ray and gamma are ionisingMonitor and minimise exposure to ionising radiation