Question 1

When electrons jump from higher levels in hydrogen atoms to the level n = 2, the resulting spectrum will consist of a

Accepted Answer

A)  continuum of light with a maximum in the visible spectral range. 
B)  series of UV lines, the Lyman series. 
C)  series of IR spectral lines, the Paschen series. 
D)  series of spectral lines, some of which are in the visible range, the Balmer series. 
A)  continuum of light with a maximum in the visible spectral range. 
B)  series of UV lines, the Lyman series. 
C)  series of IR spectral lines, the Paschen series. 
D)  series of spectral lines, some of which are in the visible range, the Balmer series.

Question 2

If curves of intensity versus wavelength are plotted for a single object at various temperatures, it is found that the curves never cross. Why is this important?

Accepted Answer

A)  If the curves do not cross, then the object is not a blackbody. 
B)  The only situation in which the curves do not cross is when the source is a neutron star-essentially an atomic nucleus the size of a star. 
C)  If the curves do not cross it means that monochromatic light has been emitted from the source. 
D)  Because each curve is unique, in theory it is possible to determine the temperature from a single point on a blackbody curve. 
A)  If the curves do not cross, then the object is not a blackbody. 
B)  The only situation in which the curves do not cross is when the source is a neutron star-essentially an atomic nucleus the size of a star. 
C)  If the curves do not cross it means that monochromatic light has been emitted from the source. 
D)  Because each curve is unique, in theory it is possible to determine the temperature from a single point on a blackbody curve.

Question 3

The series of spectral absorption lines in the infrared part of the spectrum, known as the Paschen series, results from atomic transitions in hydrogen atoms in which electrons are lifted from which energy level to all higher atomic energy levels?

Accepted Answer

A)  n = 1 level, the ground state, because all series start here 
B)  n = 3 level 
C)  ionization level 
D)  n = 2 level 
A)  n = 1 level, the ground state, because all series start here 
B)  n = 3 level 
C)  ionization level 
D)  n = 2 level

Question 4

The peak wavelength emitted in the spectrum of a blackbody is proportional to what power of the blackbody's Kelvin temperature?

Accepted Answer

A)  -4 
B)  -1 
C)  1 
D)  4 
A)  -4 
B)  -1 
C)  1 
D)  4

Question 5

An object is observed to show no Doppler shift. As a result, only one of these statements cannot describe the motion of the object. Which one?

Accepted Answer

A)  The object is stationary. 
B)  The object has only a transverse motion. 
C)  The object has only a proper motion. 
D)  The object has only a radial motion. 
A)  The object is stationary. 
B)  The object has only a transverse motion. 
C)  The object has only a proper motion. 
D)  The object has only a radial motion.

Question 6

Which of these statements is true if the star Betelgeuse has a lower surface temperature than the Sun? (Assume that IR means infrared radiation and UV means ultraviolet radiation.)

Accepted Answer

A)  Betelgeuse emits more IR and less UV flux than the Sun. 
B)  Betelgeuse emits more IR and more UV flux than the Sun. 
C)  Betelgeuse emits less IR and more UV flux than the Sun. 
D)  Betelgeuse emits less IR and less UV flux than the Sun. 
A)  Betelgeuse emits more IR and less UV flux than the Sun. 
B)  Betelgeuse emits more IR and more UV flux than the Sun. 
C)  Betelgeuse emits less IR and more UV flux than the Sun. 
D)  Betelgeuse emits less IR and less UV flux than the Sun.

Question 7

An astronomer plots the intensity of the radiation emitted from an opaque, perfectly absorbing object at a certain temperature versus its wavelength. As the temperature increases, the wavelength at which the spectrum peaks becomes shorter and shorter. This is an example of

Accepted Answer

A)  Stephan's law. 
B)  Kepler's first law. 
C)  Bode's law. 
D)  Wien's law. 
A)  Stephan's law. 
B)  Kepler's first law. 
C)  Bode's law. 
D)  Wien's law.

Question 8

Two objects are moving directly away from an observer at the same speed. One object, however, is twice as far away as the other. How do their Doppler shifts compare?

Accepted Answer

A)  They are the same. 
B)  The more distant object has the greater Doppler shift. 
C)  The more distant object has the smaller Doppler shift. 
D)  Whichever object is larger will have the greater Doppler shift. 
A)  They are the same. 
B)  The more distant object has the greater Doppler shift. 
C)  The more distant object has the smaller Doppler shift. 
D)  Whichever object is larger will have the greater Doppler shift.

Question 9

According to the Doppler effect,

Accepted Answer

A)  spectral lines are split into two or more wavelengths when the source of the light is in a strong magnetic field. 
B)  the wavelength of light is shifted to a longer wavelength if the source of the light is moving toward the observer. 
C)  the wavelength of peak emission of light from a source changes as the temperature of the source changes. 
D)  the wavelength of light is shifted to a shorter wavelength if the source of light is moving toward the observer. 
A)  spectral lines are split into two or more wavelengths when the source of the light is in a strong magnetic field. 
B)  the wavelength of light is shifted to a longer wavelength if the source of the light is moving toward the observer. 
C)  the wavelength of peak emission of light from a source changes as the temperature of the source changes. 
D)  the wavelength of light is shifted to a shorter wavelength if the source of light is moving toward the observer.

Question 10

An atom consists of

Accepted Answer

A)  negatively charged electrons moving around a very small but massive, positively charged nucleus. 
B)  neutrons orbiting an electrically neutral nucleus composed of protons and electrons. 
C)  positive protons, neutral neutrons, and negative electrons orbiting a small but massive black hole. 
D)  negatively charged electrons and positively charged protons mixed uniformly throughout the volume of the atom. 
A)  negatively charged electrons moving around a very small but massive, positively charged nucleus. 
B)  neutrons orbiting an electrically neutral nucleus composed of protons and electrons. 
C)  positive protons, neutral neutrons, and negative electrons orbiting a small but massive black hole. 
D)  negatively charged electrons and positively charged protons mixed uniformly throughout the volume of the atom.

Question 11

The minimum temperature reached on the surface of Mars, -140°C, is represented on the absolute (Kelvin) temperature scale as

Accepted Answer

A)  133 K. 
B)  153 K. 
C)  -133 K. 
D)  140 K. 
A)  133 K. 
B)  153 K. 
C)  -133 K. 
D)  140 K.

Question 12

If a certain gas is heated and observed through a grating, a bright line spectrum will be seen. If instead a source of continuous spectrum shines through a cooler sample of this same gas, a dark absorption spectrum is observed. How do the positions of the lines in these two spectra compare?

Accepted Answer

A)  All the lines in the spectrum from the hot gas will be at higher frequencies than the corresponding lines in the spectrum of the cooler gas. 
B)  All the lines in the spectrum from the hot gas will be at lower frequencies than the corresponding lines in the spectrum of the cooler gas. 
C)  The lines in the two spectra will be at the same frequencies. They will be the same spectra. 
D)  These two processes produce spectra by completely different means, and there will be no relationship at all between the two spectra. 
A)  All the lines in the spectrum from the hot gas will be at higher frequencies than the corresponding lines in the spectrum of the cooler gas. 
B)  All the lines in the spectrum from the hot gas will be at lower frequencies than the corresponding lines in the spectrum of the cooler gas. 
C)  The lines in the two spectra will be at the same frequencies. They will be the same spectra. 
D)  These two processes produce spectra by completely different means, and there will be no relationship at all between the two spectra.

Question 13

Two physicists, one on the east coast and one on the west coast of North America, discover that they have constructed ideal blackbodies in their laboratories. The two blackbodies are made from very different materials. Without conducting tests, they know that the radiation emitted by these two objects will be

Accepted Answer

A)  identical if the blackbodies are at the same temperature, but not otherwise. 
B)  identical if the blackbodies have the same size, even if their temperatures are different. 
C)  different because the blackbodies were made from different materials. 
D)  different because the amount of light falling on the blackbodies is likely to be different in the two laboratories. 
A)  identical if the blackbodies are at the same temperature, but not otherwise. 
B)  identical if the blackbodies have the same size, even if their temperatures are different. 
C)  different because the blackbodies were made from different materials. 
D)  different because the amount of light falling on the blackbodies is likely to be different in the two laboratories.

Question 14

Cepheid variable stars pulsate regularly in size. During the contraction part of the cycle, when the star's temperature is increasing, the peak wavelength of the emitted radiation will

Accepted Answer

A)  shift from the visible to the UV part of the spectrum. 
B)  shift from the UV to the visible part of the spectrum. 
C)  remain unchanged. 
D)  change randomly, independent of the temperature changes. 
A)  shift from the visible to the UV part of the spectrum. 
B)  shift from the UV to the visible part of the spectrum. 
C)  remain unchanged. 
D)  change randomly, independent of the temperature changes.

Question 15

The atomic number of the isotope 238U of uranium is 92. The nucleus of this isotope contains

Accepted Answer

A)  92 protons and 146 neutrons. 
B)  92 protons, 54 neutrons, and 92 electrons. 
C)  184 protons, 92 electrons, and 54 neutrons. 
D)  146 protons and 92 neutrons. 
A)  92 protons and 146 neutrons. 
B)  92 protons, 54 neutrons, and 92 electrons. 
C)  184 protons, 92 electrons, and 54 neutrons. 
D)  146 protons and 92 neutrons.

Question 16

Iron has 26 protons, and one isotope of iron, 57Fe, has an atomic mass of about 57. How many neutrons are in the nucleus of this atom?

Accepted Answer

A)  31 
B)  83 
C)  26 
D)  57 
A)  31 
B)  83 
C)  26 
D)  57

Question 17

Which of these are isotopes of carbon?

Accepted Answer

A)  C I and C III 
B)  (12C and 14
C)  
C)  CH3 and CH4 
D)  CH4 and C2H4 
A)  C I and C III 
B)  (12C and 14
C)  
C)  CH3 and CH4 
D)  CH4 and C2H4

Question 18

In what units does one measure flux F?

Accepted Answer

A)  joule per square meter per second 
B)  joule per second 
C)  joule per square meter per second per Kelvin degree 
D)  joule times square meter per second 
A)  joule per square meter per second 
B)  joule per second 
C)  joule per square meter per second per Kelvin degree 
D)  joule times square meter per second

Question 19

The hot, dense gas existing on the Sun emits energy

Accepted Answer

A)  only at certain wavelengths and not at other wavelengths. 
B)  at all wavelengths, with a peak at one particular wavelength (color). 
C)  mostly at the longest and shortest wavelengths, with a minimum in between. 
D)  with the same intensity at all wavelengths. Earth's atmosphere absorbs radiation at both short and long visible wavelengths to produce the observed spectrum. 
A)  only at certain wavelengths and not at other wavelengths. 
B)  at all wavelengths, with a peak at one particular wavelength (color). 
C)  mostly at the longest and shortest wavelengths, with a minimum in between. 
D)  with the same intensity at all wavelengths. Earth's atmosphere absorbs radiation at both short and long visible wavelengths to produce the observed spectrum.

Question 20

A particular spectrograph, used by an astronomer to disperse light into its colors, contains a piece of glass that has been ruled with thousands of closely spaced, parallel lines. What is the name of this piece of glass?

Accepted Answer

A)  interferometer 
B)  CCD array 
C)  diffraction grating 
D)  prism 
A)  interferometer 
B)  CCD array 
C)  diffraction grating 
D)  prism

When electrons jump from higher levels in hydrogen atoms to the level n = 2, the resulting spectrum will consist of a

If curves of intensity versus wavelength are plotted for a single object at various temperatures, it is found that the curves never cross. Why is this important?

The series of spectral absorption lines in the infrared part of the spectrum, known as the Paschen series, results from atomic transitions in hydrogen atoms in which electrons are lifted from which energy level to all higher atomic energy levels?

The peak wavelength emitted in the spectrum of a blackbody is proportional to what power of the blackbody's Kelvin temperature?

An object is observed to show no Doppler shift. As a result, only one of these statements cannot describe the motion of the object. Which one?

Which of these statements is true if the star Betelgeuse has a lower surface temperature than the Sun? (Assume that IR means infrared radiation and UV means ultraviolet radiation.)

An astronomer plots the intensity of the radiation emitted from an opaque, perfectly absorbing object at a certain temperature versus its wavelength. As the temperature increases, the wavelength at which the spectrum peaks becomes shorter and shorter. This is an example of

Two objects are moving directly away from an observer at the same speed. One object, however, is twice as far away as the other. How do their Doppler shifts compare?

According to the Doppler effect,

An atom consists of

The minimum temperature reached on the surface of Mars, -140°C, is represented on the absolute (Kelvin) temperature scale as

If a certain gas is heated and observed through a grating, a bright line spectrum will be seen. If instead a source of continuous spectrum shines through a cooler sample of this same gas, a dark absorption spectrum is observed. How do the positions of the lines in these two spectra compare?

Cepheid variable stars pulsate regularly in size. During the contraction part of the cycle, when the star's temperature is increasing, the peak wavelength of the emitted radiation will

The atomic number of the isotope ²³⁸U of uranium is 92. The nucleus of this isotope contains

Iron has 26 protons, and one isotope of iron, ⁵⁷Fe, has an atomic mass of about 57. How many neutrons are in the nucleus of this atom?

Which of these are isotopes of carbon?

In what units does one measure flux F?

The hot, dense gas existing on the Sun emits energy

A particular spectrograph, used by an astronomer to disperse light into its colors, contains a piece of glass that has been ruled with thousands of closely spaced, parallel lines. What is the name of this piece of glass?

Discovering the Night Sky

Gravitation and the Motion of the Planets

Light and Telescopes

Exoplanets and the Formation of Planetary Systems

Formation of the Solar System

Earth and the Moon

The Other Terrestrial Planets

The Outer Planets

Vagabonds of the Solar System

The Sun: Our Extraordinary Star

Characterizing Stars

The Lives of Stars From Birth Through Middle Age

The Death of Stars

Black Holes: Matters of Gravity

The Milky Way Galaxy

Galaxies

Quasars and Other Active Galaxies

Cosmology

Astrobiology

Filters

Exam 4: Atomic Physics and Spectra

When electrons jump from higher levels in hydrogen atoms to the level n = 2, the resulting spectrum will consist of a

If curves of intensity versus wavelength are plotted for a single object at various temperatures, it is found that the curves never cross. Why is this important?

The series of spectral absorption lines in the infrared part of the spectrum, known as the Paschen series, results from atomic transitions in hydrogen atoms in which electrons are lifted from which energy level to all higher atomic energy levels?

The peak wavelength emitted in the spectrum of a blackbody is proportional to what power of the blackbody's Kelvin temperature?

An object is observed to show no Doppler shift. As a result, only one of these statements cannot describe the motion of the object. Which one?

Which of these statements is true if the star Betelgeuse has a lower surface temperature than the Sun? (Assume that IR means infrared radiation and UV means ultraviolet radiation.)

An astronomer plots the intensity of the radiation emitted from an opaque, perfectly absorbing object at a certain temperature versus its wavelength. As the temperature increases, the wavelength at which the spectrum peaks becomes shorter and shorter. This is an example of

Two objects are moving directly away from an observer at the same speed. One object, however, is twice as far away as the other. How do their Doppler shifts compare?

According to the Doppler effect,

An atom consists of

The minimum temperature reached on the surface of Mars, -140°C, is represented on the absolute (Kelvin) temperature scale as

If a certain gas is heated and observed through a grating, a bright line spectrum will be seen. If instead a source of continuous spectrum shines through a cooler sample of this same gas, a dark absorption spectrum is observed. How do the positions of the lines in these two spectra compare?

Cepheid variable stars pulsate regularly in size. During the contraction part of the cycle, when the star's temperature is increasing, the peak wavelength of the emitted radiation will

The atomic number of the isotope 238U of uranium is 92. The nucleus of this isotope contains

Iron has 26 protons, and one isotope of iron, 57Fe, has an atomic mass of about 57. How many neutrons are in the nucleus of this atom?

Which of these are isotopes of carbon?

In what units does one measure flux F?

The hot, dense gas existing on the Sun emits energy

A particular spectrograph, used by an astronomer to disperse light into its colors, contains a piece of glass that has been ruled with thousands of closely spaced, parallel lines. What is the name of this piece of glass?

Discovering the Night Sky

Gravitation and the Motion of the Planets

Light and Telescopes

Exoplanets and the Formation of Planetary Systems

Formation of the Solar System

Earth and the Moon

The Other Terrestrial Planets

The Outer Planets

Vagabonds of the Solar System

The Sun: Our Extraordinary Star

Characterizing Stars

The Lives of Stars From Birth Through Middle Age

The Death of Stars

Black Holes: Matters of Gravity

The Milky Way Galaxy

Galaxies

Quasars and Other Active Galaxies

Cosmology

Astrobiology

Filters

The atomic number of the isotope ²³⁸U of uranium is 92. The nucleus of this isotope contains

Iron has 26 protons, and one isotope of iron, ⁵⁷Fe, has an atomic mass of about 57. How many neutrons are in the nucleus of this atom?