Astronomy Chapter 5

Gamma, X, UV, Visible, Infrared, radio

rate of energy flow, measured in WATTS 1 watt=1 joule/s

a piece of plastic or glass etched with many closely spaced lines (e.g DVD)

energy of the light comes from the electrical potential supplied to the object (e.g) lightbulb

materials that absorb are called opaque

allowing light to pass through

light bouncing off matter

distance from one peak to the next

number of peaks by any point each second, measured in cycles per second or Hertz

wavelength times frequency

They have a frequency of 2 hertz.

They have different numbers of protons in their nucleus

the strength of a force that a particle would experience at any point in space

light waves travel in vibrations of both electric and magnetic fields

(c) about 300,000 kilometers/sec

where light travels, have properties of waves and particles

the wavelengths of spectral lines in the star's spectrum

have wavelengths that are longer than normal

1. Stephan Boltzann's Law: Each square meter of a hotter object's surf ac emits more light at all wavelengths. 2. Wien's Law: Hotter objects emit photons with a higher average energy.

shorter average wavelength

radiation with a spectrum whose shape depends only on the temperature of the emitting object

An emission line spectrum consists of bright lines on a dark background, while an absorption line spectrum consists of dark lines on a rainbow background

absorbs ultraviolet light

a thermal radiation spectrum.

the wavelength of a spectral feature in the absence of any Doppler shift or gravitational red shift

the effect that shifts the wavelengths of spectral features in objects that are moving toward or away from earth

chemical composition

cooler

redshifted.

Energy is what makes matter move. It is measured in joules. Power is the rate of which the energy flows. Power is measured in watts, which is 1 joule per second

A photon is an individual piece of light. A photon is like a particle because they can be counted individually, and can hit surfaces one at a time. They are like waves because they are also characterized by wavelength and frequency, A photon is a particle of light. Unlike an ordinary wave, light has a smallest unit that cannot be subdivided. However, light also has wavelike properties, such as having characteristic wavelengths and frequencies.

We say that light is an electromagnetic wave because light is a vibration of electric and magnetic fields. Because all electromagnetic waves travel at the speed of light, the product of their frequencies and wavelengths is always the speed of light. (This is because the product of frequency and wavelength is always the speed of the wave. For light, that speed is constant.) Mathematically: frequency = speed of light/wavelength An electromagnetic wave is a synonym for light, because it consists of waves of electric and magnetic fields. Wavelength is the distance from one peak of an electromagnetic wave to the next. Frequency is the number of peaks passing by any point each second. The speed of the waves determine how fast their peaks travel. The speed of a wave can be determined by the wavelength multiplied by the frequency

Yes, Our bodies, including our eyelids, emit infrared radiation. Therefor, we would see the infrared light emitting from our eyelids when we closed them

6,000 joules

The Sun's hot interior produces a continuous rainbow of color, but cooler gas at the surface absorbs light at particular wavelengths.

the approximate temperature of the Sun's surface

Compare the wavelengths of lines in the Sun's spectrum to the wavelengths of lines produced by chemical elements in the laboratory.

The radio waves from the radio station are causing electrons in your radio's antenna to move up and down 97 million times each second.

Frequency is related to wavelength by the formula: wavelength ( frequency = speed of light = 300 million m/s. Thus, for a frequency of 300 million hertz, the wavelength is 1 meter, since 1 m ( 300 million /s = 300 million m/s.

The passage of a light wave can cause electrically charged particles to move up and down.

They are isotopes both atoms have the same atomic number but different atomic mass numbers number: # protons mass: #protons and neutrons

Charge = +2; number of remaining electrons = 6. Because oxygen has 8 protons, it must also have 8 electrons when it is neutral. Doubly ionized means two electrons are missing, leaving only 6 electrons and an overall charge of 8-6= +2.

The cloud is cool and lies between you and a hot star.

The two spectra would have similar shapes, except Neptune's spectrum would be missing a big chunk of the red light that is present in the Sun's spectrum

The temperature of the corona's gas is some 1 to 2 million Kelvin.

The star is moving toward us.

The faster rotating star has wider spectral lines than the slower rotating star. Fast rotation will widen spectral lines because there is a greater difference in the Doppler shift from the side of the star rotating toward us and the side rotating away from us

It's like a particle b/c they can be counted individually and can hit surfaces one at a time. And they're like waves because each one is characterized by the same properties as waves (like wavelength and frequency).

A molecule is when atoms of the same element combine.

Electrical charge is a fundamental property that describes how strongly an object will interact in electromagnetic fields. Protons and electrons would attract, but electrons and electrons would not attract.

ice changes to liquid at the melting point; liquid changes to gas at the boiling point, At very high temperatures, sublimation (the process when molecules escape from a solid) and evaporation (when molecules escape from a liquid) occur much easier and more often. Molecular dissociation, Plasma phase, Fully ionized plasma are the next three phase changes of water with increasing temperature. Plasma is a hot gas including freely moving electrons and positively charged hydrogen and oxygen ions. Basically, it's when the atoms have become ionized (electrons are stripped from atoms) ex's. solid=desk, liquid=beer, gas=nitrogen, plasma=fluorescent lights

Quantized means that they are sudden changes with no in-between level. Energy level transitions can occur only when an electron gains or loses the exact amount of energy that separates two energy levels. Level 1=0-10.2, Level 2=10.2-12.1, Level 3=12.1-12.8 and Level 4= 12.8-13.6, then Ionization meaning the electron escapes the atom completely (ionizing it)

Through spectroscopy. And then changing them from showing only visible light to showing the amount of radiation, or intensity, at each wavelength.

Continuous: light bulb produces light of all colors Ex. Incandescent light bulb Emission Line: gas cloud emits light at specific colors depending on its composition and temperature Absorption Line: Light from a hot source passes through a cooler gas cloud (which absorbs certain wavelengths [colors])

An 8,000K star would emit a lot more light at every wavelength than the 4,000K- sometimes in places where the cooler star wont emit light at all-making it bluer. (shorter wavelengths). -Hotter star emits photons with a higher average KE (makes the peaks of the graph at shorter wavelengths for hotter objects).

The Doppler Effect is when the wavelengths of spectral lines are slightly shifted depending on the velocity of the light and whether it is moving towards or away from us as it orbits the Sun. Blue-shifted (closer together) radio waves means the object is moving towards us. The Doppler effect widens the spectral lines of rotating objects because the wavelengths changes from blue or red. Blue-shifted, red-shifted, and non-shifted photons mix together to get how its rotating.

more & more

LIGHT

solid to gas