NATS 1745 Lecture Notes - Lecture 3: Radiography, Electromagnetic Spectrum, Black Body
22 Jan 2018
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Document Summary
Light- behaviours like a wave that travel through empty space. Wavelength- distance from one peak to the next. Measured in fractions of a meter: nanometers (nm) billionth of 1-metre. 1- our eye responds to the different wavelengths as we perceive different colours, colour generated by eye and our brain. Visible light is one small part of whole electromagnetic spectrum. Gamma rays (short wave length) (high frequency) (high energy) Radio (long wave length) (low frequency) (low energy) All wavelengths travel at same speed =speed of light. Frequency (f) is number of peaks that lass a point in 1-second. A particle of light is a photon, each photon has a specific amount of energy, which relates directly to wavelength and frequency. Astronomy techniques direct imaging- tells us what objects look like. If you use all wavelength of visible light, images will appear as human eye would see.
