Astronomy Chapter 4 Flashcards

Questions and Answers

What is spectroscopy?

A study of the geometry of rainbows

The use of CCDs to capture light more efficiently than with photographic film

A method to freeze atmospheric turbulence for better resolution

An observational technique to measure the brightness of light at different colors

An analysis of the way in which atoms absorb and emit light (correct)

In the atom, which particles give the element its identity (atomic number)?

Protons (correct)

Electrons

Neutrinos

Positrons

Neutrons

The particles which enter into chemical reactions are the atom's:

Electrons (correct)

Positrons

Mesons

Protons

Neutrons

A hydrogen atom consists of an electron and a(n):

Proton Signup and view all the answers

The particle which adds mass but no charge to the atomic nucleus is the:

Neutron Signup and view all the answers

An emission spectrum can be used to identify a(n):

Atom Signup and view all the answers

In Bohr's model of the atom, electrons:

Only make transitions between orbitals of specific energies Signup and view all the answers

In space, positive ions are the result of:

Electrons being stripped off the outer electron shell for hot atoms Signup and view all the answers

Typical stellar spectra appear as:

A rainbow, but with some dark lines mixed in Signup and view all the answers

To have a negative ion, you must have:

Added an electron to the outer electron shell Signup and view all the answers

For hydrogen, the transition from the second to the fourth energy level produces:

A blue green absorption line Signup and view all the answers

A heavy neutral atom, such as iron, produces many spectral lines compared to light elements like hydrogen and helium. Why?

Because of the larger number of electrons and corresponding energy levels, more transitions are possible Signup and view all the answers

Which of these is the classic continuous spectrum?

A rainbow Signup and view all the answers

Why are molecular lines more complex than elemental spectral lines?

Molecules can vibrate and rotate as well Signup and view all the answers

The splitting of spectral lines in the presence of strong magnetic fields is the:

Zeeman effect Signup and view all the answers

Spectral lines are often referred to as the stars' 'fingerprints' because:

All of these are correct Signup and view all the answers

The broadening of spectral lines can be caused by:

All of the above Signup and view all the answers

According to the Zeeman effect, the splitting of a sunspot's spectral lines is due to:

Their magnetic fields Signup and view all the answers

What information about an astronomical object can be determined by observing its spectrum?

All of the above Signup and view all the answers

The Orion Nebula, M-42, is a hot, thin cloud of glowing gas, so its spectrum is:

A few bright lines against a dark background Signup and view all the answers

An incandescent light (glowing tungsten filament) produces:

A continuous spectrum, with the peak giving the temperature of the filament Signup and view all the answers

A neon light (thin hot neon gas in a sealed tube) gives us:

A few bright emission lines, telling us the gas is neon Signup and view all the answers

Study Notes

Spectroscopy and Atomic Structure

Spectroscopy involves analyzing how atoms absorb and emit light, providing insight into elemental identity.
Protons define an element's atomic number, distinguishing one element from another.
Electrons are the particles that participate in chemical reactions, influencing chemical behavior and bonding.

Hydrogen Atom Composition

A hydrogen atom comprises one electron and one proton, fundamental for understanding molecular formation.

Neutrons and Atomic Mass

Neutrons contribute mass to the atomic nucleus without adding electrical charge, essential in isotopic variation.

Emission and Absorption

An emission spectrum can identify specific atoms, reacting predictably to varying energy states.
In Bohr's atomic model, electrons transition strictly between defined energy levels, dictating their radiative properties.

Ionization and Stellar Spectra

Positive ions in space result from electrons being stripped from outer shells of hot atoms during energetic processes.
Stellar spectra typically display as a rainbow interspersed with dark lines (absorption lines), characteristic of elements present.

Ion Formation and Spectral Lines

Negative ions form when an additional electron is added to an atom's outer shell, affecting the atom's charge balance.
The transition in hydrogen from the second to the fourth energy level produces a blue-green absorption line, revealing electron behavior.

Complex Spectral Emissions

Heavier atoms, like iron, generate complex spectra due to a larger number of electrons and energy transitions available.
Molecular spectral lines are more intricate than those of elemental atoms due to additional vibrational and rotational states.

Zeeman Effect and Spectral Broadening

The Zeeman effect describes the splitting of spectral lines in strong magnetic fields, providing insights into magnetic properties.
Spectral line broadening can result from various factors including magnetic fields, atom density, thermal motion, and stellar rotation.

Information from Spectra

Spectra enable the determination of an astronomical object's magnetic field strength, chemical composition, radial motion, and temperature, crucial for astrophysical analysis.

Nebulae and Light Sources

The Orion Nebula's spectrum presents bright lines on a dark background, indicating its hot, glowing gas composition.
Incandescent light sources produce a continuous spectrum with a temperature peak indicating thermal properties.
Neon lights emit distinct bright lines, signaling the presence of neon gas through their unique spectral emissions.

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Test your knowledge of spectroscopy and other key concepts from Astronomy Chapter 4. These flashcards are designed to help you understand how atoms interact with light. Quiz yourself to reinforce your learning and prepare for exams!