astronomy notes chapter 5 - (when the bouncing is more...

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Chapter 5 The energy that light carries is called radiative energy. Three basic categories of life include kenitc, potential and radiative energy. Energy is measured in units of joules. The rate of energy flow is called power, which is measured in watts. One watt is equal to one joule. Light from the sun or a light bulb is called white light. Emission : a light bulb emits visible light; the energy of the light comes from electrical potential energy supplied to the light bulb. Absorption : When you place your hand near an incandescent light bulb, our hands absorbs some of the light, and the absorbed energy warms your hand. Transmission : Some forms of matter, such as glass or air, transmit light. That is, they allow light to pass through. Reflection/scattering : Light can bounce off matter leading to what we call reflection (when the bouncing is all in the same general direction) or scattering
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Unformatted text preview: (when the bouncing is more random) • Materials that transmit light are said to be transparent. And materials that absorb light are called opaque. • Light behaves like waves. • Waves carry energy outward from the place where the pebble landed but do not carry matter along with them. • Wavelength : the distance from one peak to the next. • Frequency : The number of peaks passing by any point each second • Wavelength*frequency=speed • The Doppler shift of an object coming toward us is called BLUESHIFT. • If an object is moving away from us, its light is shifted to longer wavelengths is called REDSHIFT because longer wavelengths of visible light are redder. • The Doppler shift tells us only the part of an object’s full motion that is directed toward or away from us. •...
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This note was uploaded on 05/01/2010 for the course ASTR 1010 taught by Professor Sethhoreinstin during the Spring '10 term at University of Illinois, Urbana Champaign.

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astronomy notes chapter 5 - (when the bouncing is more...

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