Learning From Light Flashcards
Spectrum
The light we see.
Spectra* - (Mix of energies (wavelengths) and blue and red light)
Brightness
Amount of light measured (depends on distance)
Synonyms: Intensity and Flux
Luminosity
Amount of energy an object radiates
What can telescopes do? (3)
- Collect a lot of light.
- Increase resolution of images to show fine details.
- Magnify.
Refracting Telescopes
Uses lenses to focus light
Reflecting Telescope
Uses mirrors to focus light
What type of wavebands can telescopes be built for?
Optical, X-Ray, Radio, etc.
Where are telescopes usually built?
High and dry places to minimize scattering.
Why are there space telescopes? What wavebands are they used for.
Space telescopes are built because some light is absorbed by the Earth’s atmosphere.
Gamma, X-Ray, Ultra-Violet, Infrared, (Some) Visible Light
How is light made? (3)
- Hot, Opaque objects. (Stars!)
- Hot gas clouds. (Nebulae!)
- High Energy Systems. (Neutron Stars, etc.)
Thermal Radiation
HOT OPAQUE OBJECT: Energy is emitted by a heated surface in all directions. (Glow)
The Peak of intensity is during red light.
Order the color of light from hottest to coldest.
Blue, Yellow, Red
Rules for Thermal Radiaton
As temperature increases, the distinctive spectrum shifts bluer and brighter as temperature increases.
The Peak of the spectrum is deterred by temperature.
What did Fraunhofer discover?
Spectral Lines
What do Spectral Lines do?
Atomic fingerprint; used to identify atoms.
Atoms absorb and emit photons but only photons with certain energies.
