Unit 7: Light and Matter- The Sun Flashcards
Why does a heated Iron poker glow?
- Emits photons of visible light
- As the object heats up, it gets brighter, emitting more photons of all colors (wavelengths). Brightness (intensity of radiation) is the #of photons emitted per second increases
What is the color of the brightest/ most intense wavelength?
Shifts towards the violet end of the spectrum as the temperature increases.
What is Blackbody Radiation?
A theoretical or model body which absorbs all radiation falling on it, reflecting or transmitting none
- A blackbody absorbs and emits entire spectrum of electromagnetic radiation.
Do photons with a shorter wavelength carry more or less energy than a photon with a linger wavelength?
More
- red, orange, yellow, green, blue, violet (least to most energy)
How are elements arranged on the Periodic Table of Elements?
They are arranged in order of increasing number of protons (atomic number)
How are the elements in each column related?
They have similar chemical properties
What are spectral lines and when do they occur?
- When an electron jumps from one energy level (or ‘Orbit’) to another
(Absorption and Emission)
What is a Spectroscope used for?
To examine the wavelengths of light emitted from a source
What are the steps of a spectroscope?
- Add a chemical substance to a flame
- send light from the flame through a narrow slit then through lenses and a prism
- Bright lines in the spectrum show the the substance emits light at specific wavelengths only
What is the Absorption Spectrum for Hydrogen Gas?
The line appears as dips in the intensity vs wavelength graph
What is the Emission Spectrum for Hydrogen Gas?
flat intensity at 0
with spikes in intensity as wavelengths increase
What are the Two kinds of Glowing Gas Clouds?
Hydrogen and Oxygen rich clouds
What color are Hydrogen Rich Glowing clouds?
These clouds glow red
What color are Oxygen Rich Glowing clouds?
These clouds glow green
What is the Doppler Effect?
The wavelength of light is slightly shifted when the source is traveling toward or away from the observer
What are the two types of shifts seen in the Doppler Effect?
Red and blue shifts
What Is a red shift?
When stars are moving away from us, The spectral lines are shifted to red
What is a blue shift?
When stars are moving toward us, the spectral lines shifted to blue
The amount of the Doppler Effect shift increases with what?
The amount of shift increases with the radial speed
Explain the spectral lines of the star Vega?
They are all shifted towards the blue side, which means Vega is moving towards our place at ~14km/s
What is the proper motion of a star?
The proper motion of a star is its motion perpendicular (right angle) to our line of sight across the celestial sphere. This is so small that it can only be measured for the closest stars
What is the radial velocity of a star?
The radial velocity of a star is its motion along our line of sight either toward or away from us, Thanks to the Doppler effect
How far is the sun from the earth?
1 AU or 1.496x10^8km
What is the suns mass
10^5 earth masses
The combined mass of objects orbiting the sun is?
0.15% of the sun’s mass
The global gross capacity for the sun is
3.4x10^11W
1 second for the sun= 35 million years for us
What is the sun’s inner structure?
Core
Radiative Zone
Convection Zone
Describe the Sun’s Core
The middle of the sun
The sun’s energy is released here by the fusion of hydrogen into helium
Describe the Sun’s Radiative Zone
So called as energy is transferred by means of radiation.
Describe the Sun’s Convection Zone
So called as energy is transferred by means of convection
Describe the magnetic field of the sun
160,000 km
100km/s
What are Solar Flares
Violent eruptions called solar flares eject huge amounts of solar gases into space.
What does the word Photosphere mean and what is it?
It is the deepest layer of the Sun you can see
- the word photosphere means light sphere
What is the size of the suns photosphere
500km thick
What are sunspots and granules
A granule is a convection cell in the Sun’s Photosphere
Sunspots are the darker spots, they are cooler than the earth surface
The number of sunspots on the photosphere varies over an ________ year period?
11 year cycle
What is the Chromosphere and what does it mean?
Colourful layer around the sun is called the chromosphere. It means “color sphere”
How big is the chromosphere
2000-3000 km thick
What is a Corona?
the suns atmosphere
- extremely dilute and hot
(looks like white light around the sun)
When was the source of the suns energy understood
20th C
What is the temperature of the suns core?
15.5MK
What is the pressure of the suns core
340Gbar
What is the density of the suns core
160 tons/ M^3
What is the Hydrogen Fusion reaction equation
4H = He= energy
The mass of 4 hydrogen atoms - 1 helium atom= mass lost
How many tons of hydrogen get turned into helium in the suns core every second
600 million metric tons
How much hydrogen does the sun contain and how long will it last
The sun contains enough hydrogen to continue to the present rate of energy output for another 5 billion years
