
Concept explainers
Whether the reason for describing the reddish H II region as red hot is the same that for the filament of an electric toaster.

Answer to Problem 1CC
Solution:
The filament of an electric toaster is blackbody that is why it glows whereas the reason for the reddish H II region is the emitted light due to the transition from
Explanation of Solution
Introduction:
The notation used by the astronomers for the neutral hydrogen atoms that are not ionized is H I and for the hydrogen atoms that are ionized is H II. The emission nebulae primarily consists of hydrogen atoms that are ionized, meaning free protons and free electrons.
Explanation:
A nearby hot star emits high energy ultra-violet photons which are absorbed by the hydrogen atoms in the nebulae. These hydrogen atoms gain energy to get ionized into electrons and protons. These free protons and free electrons recombine to form hydrogen atoms through a process known as recombination. When the hydrogen atom forms by recombination, the electron is usually captured in a large, energetic orbit of the proton. This electron makes a transition to successive lower energy orbits. With each transition, a photon is emitted and each of these photons are less energetic and have a longer wavelength than that compared to the photons emitted from a hot star initially. Among all of the transitions, the important transition is from
The black bodies absorb the entire
Conclusion:
The reddish H II region appears because of the emitted light in the red region of the visible spectrum.
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Chapter 18 Solutions
Universe
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