Fusion & Star Spectra Flashcards
How does nuclear fusion occur?
When two nuclei combine (fuse) to create a larger nucleus
How does nuclear fusion occur in stars?
When hydrogen nuclei fuse together to make helium nuclei
How does energy and mass change during nuclear fusion?
Nuclei lose mass and energy is released
What is ‘E’ in the formula E=mc2?
Amount of energy released
What is ‘m’ in the formula E=mc2?
Amount of mass lost
What is ‘c’ in the formula E=mc2?
Speed of light in a vacuum
What are continuous spectra?
A spectrum emitted by hot objects that contain all possible frequencies
What is the peak frequency?
The one frequency that is emitted more than any other by a certain object
What does the peak frequency depend on?
The temperature: the higher the temperature, the more energy the photons radiated will have so the higher the peak frequency
What kind of frequency does a star glowing red have?
A low frequency, it’s called a cool star
What kind of frequency does a star glowing blue have?
A high requency, it’s called a scorchio
What is absorption spectra?
At high temperatures, the electrons change to higher energy levels by absorbing radiation and particular frequencies.
When can you see absorption spectra?
If a continuous spectrum of visible light shines through a gas then you would see gaps of dark lines (sbsorption lines) in the spectrum
What is emission spectra?
When electrons in higher energy levels are unstable and fall from higher to lower levels. This loses them energy by emitting radiation of a particular frequency, giving a series of bright lines
How do astronomers use spectra?
They look at the position of the esmission and absorption lines in a spectrum and compare it to known spectra
