Chap 4 – Space
Flashcard maker : Julia Rush
What is spectroscopy?
an analysis of the way in which atoms absorb and emit light
Typical stellar spectra appear as:
a rainbow, but with some dark lines mixed in.
Which of these is the classic continuous spectrum?
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.
The three laws dealing with the creation of various spectra are due to:
The Fraunhofer lines in the solar spectrum are actually:
absorption lines due to the thin outer layer above the photosphere.
The element first found in the Sun’s spectrum, then on Earth 30 years later, is:
An incandescent light (glowing tungsten filament) produces:
a continuous spectrum, with the peak giving the temperature of the filament.
A neon light (thin hot neon gas in a sealed tube) gives us:
a few bright emission lines, telling us the gas is neon.
The energy required to ionize a hydrogen atom whose electron is in the ground state (energy level 1) is:
The energy required to move an electron in a hydrogen atom from energy level 1 to energy level 2 is:
The energy required to move an electron in a hydrogen atom from energy level 2 to energy level 3 is:
The Balmer Beta absorption line is a result of a transition of an electron in a hydrogen atom from:
level 2 to level 4.
Only a hot, thin gas can produce an emission line.
The absorption lines for a cool thin gas are identical in color and energy to the emission lines of the same gas if hot enough to glow.
The spectral lines of each element are distinctive to that element, whether we are looking at emission or absorption lines.
A low-density, hot gas produces a continuous spectrum.
A low density gas must be hot in order to produce an absorption line.
A cool, thin gas produces absorption lines.
An X-ray photon has more energy than a visible photon.
In the atom, which particles give the element its identity (atomic number)?
The particles which enter into chemical reactions are the atom’s:
A hydrogen atom consists of an electron and a(n):
The particle which adds mass but no charge to the atomic nucleus is the:
An emission spectrum can be used to identify a(n):
The classical model of the hydrogen atom that explains its spectral line structure is due to:
Which of the following type of electromagnetic radiation has the highest energy?
Which of the following type of electromagnetic radiation has the lowest energy?
In Bohr’s model of the atom, electrons:
only make transitions between orbitals of specific energies.
In space, positive ions are the result of:
electrons being stripped off the outer electron shell for hot atoms.
According to the photoelectric effect in order to release electrons from a solid, the light incident upon it must:
have a short wavelength.
The shorter a wave’s wavelength, the greater its energy.
In the Bohr model, the transitions of electrons down to ground state produce the Lyman lines in the ultraviolet.
The Balmer lines of hydrogen involve electron transitions from the ground state to higher levels.
The red hydrogen alpha line carries more energy per photon than the blue-green hydrogen beta line does.
All wavelengths of light travel at the same speed in a vacuum, and carry the same energy per photon.
In an atom, electrons can have only specific, allowed orbital energies.
Emission lines of hydrogen that are found in the ultraviolet part of the electromagnetic spectrum are formed by electrons transitioning from:
any level to level 1.
To have a negative ion, you must have:
added an electron to the outer electron shell.
For hydrogen, the transition from the second to the fourth energy level produces:
a blue green absorption line.
In a hydrogen atom, a transition from the third to the second energy level will produce:
a red emission line.
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.
Molecular spectra, like elemental ones, involve only the vibration of the particles.
Why are molecular lines more complex than elemental spectral lines?
Molecules can vibrate and rotate as well.
Since the difference in energy between the different rotational states in a molecule is very small, many molecular lines can be observed with:
radio or microwave telescopes.
The splitting of spectral lines in the presence of strong magnetic fields is the:
Spectral lines are often referred to as the stars’ “fingerprints” because:
All of these are correct.
If a source of light is approaching us at 3,000 km/sec, then all its waves are:
blue shifted by 1%.
The observed spectral lines of a star are all shifted towards the red end of the spectrum. Which statement is true?
This is an example of the Doppler effect.
The broadening of spectral lines can be caused by:
All of the above
According to the Zeeman effect, the splitting of a sunspot’s spectral lines is due to:
their magnetic fields.
If the rest wavelength of a certain line is 600 nm, but we observe it at 594 nm, then:
the source is approaching us at 1 % of the speed of light.
What information about an astronomical object can be determined by observing its spectrum?
All of the above
The larger the redshift, the faster the distant galaxy is rushing toward us.
If a fire truck’s siren is rising in pitch, it must be approaching us.
Spectroscopy of a star can reveal its temperature, composition, and line-of-sight motion.
The Doppler effect can reveal the rotation speed of a star by the splitting of the spectral lines.
The radial velocity of a star’s motion in space can also broaden its spectral lines.
The Zeeman effect reveals the presence of strong magnetic fields by the splitting of spectral lines.
The broader the spectral line, the higher the pressure of the gas that is creating it.
The line intensity of a spectrum depends both on the abundance of a particular element and its temperature as well.
In our Sun, the spectral lines of hydrogen are weak, compared to their appearance in hotter stars.