Question 1

The range of temperatures in the Kelvin (absolute)  scale between the freezing point and boiling point of water is

Accepted Answer

A)   100 degrees.
B)   212 degrees.
C)   10 degrees.
D)   273 degrees.

Question 2

The energy flux, F, emitted by a star is the amount of

Accepted Answer

A)   energy emitted by the entire star each second.
B)   incoming light reflected by the star each second.
C)   energy emitted by each square meter of the star's surface each second.
D)   energy emitted by the star over its lifetime.

Question 3

The Lyman series of ultraviolet spectral emission lines from hydrogen gas is produced by electrons jumping

Accepted Answer

A)   to the first excited level from all higher levels.
B)   to the ground state from all other energy levels.
C)   between adjacent energy levels, n = 2 to n = 1, n = 3 to n = 2, n = 4 to n = 3, and so on.
D)   from the continuum level to all other levels.

Question 4

Ionization of an atom occurs when

Accepted Answer

A)   an electron is removed from the atom.
B)   the nucleus is split, or fission occurs.
C)   an electron is lifted from the ground state to an excited level.
D)   an electron drops from a higher energy level to the ground state.

Question 5

How many electrons surround the nucleus of a triply ionized magnesium atom, Mg IV? The atomic number of magnesium is 12.

Accepted Answer

A)   9
B)   12
C)   11
D)   15

Question 6

The Kelvin scale measures

Accepted Answer

A)   temperature in Fahrenheit-sized degrees above absolute zero.
B)   temperature referenced to zero at the freezing point of water.
C)   mass per unit volume, or density, with water having a value of 1.0.
D)   temperature in Celsius-sized degrees above absolute zero.

Question 7

An astronomer measures the spectrum of a star and finds a spectral line at 499 nm wavelength. In the laboratory, this spectral line occurs at 500 nm. According to the Doppler effect, this object is moving _____ Earth at _____the speed of light.

Accepted Answer

A)   toward; 1/500
B)   away from; 1/500
C)   toward; 499/500
D)   away from; 499/500

Question 8

O III is

Accepted Answer

A)   4-times-ionized oxygen (an oxygen atom that has lost 4 electrons) .
B)   doubly ionized oxygen (an oxygen atom that has lost 2 electrons) .
C)   an oxygen isotope with 3 neutrons.
D)   3-times-ionized oxygen (an oxygen atom that has lost 3 electrons) .

Question 9

Interstellar space (the space between the stars)  is filled with extremely low-density hydrogen gas. In the vicinity of a hot star, this gas can be heated to a very high temperature. This hot, low-density gas will

Accepted Answer

A)   emit light at specific wavelengths characteristic of hydrogen, among other elements.
B)   emit light at all wavelengths in a blackbody spectrum, with emission lines characteristic of hydrogen superimposed on the spectrum.
C)   emit light at all wavelengths in a blackbody spectrum characteristic of a hot gas.
D)   reflect light at specific wavelengths characteristic of hydrogen.

Question 10

If light from a hot, dense star passes through a cool cloud of gas,

Accepted Answer

A)   the atoms of the gas cloud will add energy to the overall spectrum, enhancing it at specific wavelengths to produce emission lines.
B)   the cool gas will not affect the spectrum of the star because cool atoms cannot absorb light.
C)   the whole spectrum will be reduced in intensity.
D)   only specific wavelengths of light will be removed from the spectrum.

Question 11

The Sun's spectrum peaks in the yellow-green region (i.e., this region is the most intense part of its spectrum) . The spectrum of Rigel (the star in the knee of Rigel)  peaks in the short-wavelength end of the visible spectrum. Compared with the Sun, Rigel is

Accepted Answer

A)   cooler and redder.
B)   cooler and whiter.
C)   hotter and redder.
D)   hotter and whiter.

Question 12

The mass of the electrically neutral particle, the neutron, which is one component of the atomic nucleus along with the proton, is _____ the mass of the proton.

Accepted Answer

A)   about twice
B)   about the same as
C)   2000 times less than
D)   200 times greater than

Question 13

The spectrum of a star shows a set of dark absorption lines equivalent to the absorption lines of the Sun but with one exception: Every line appears at a slightly longer wavelength, shifted toward the red end of the spectrum. What conclusion can be drawn from this observation?

Accepted Answer

A)   A cloud of cold gas and dust surrounds the star and is absorbing light from it.
B)   The star is moving toward Earth.
C)   The temperature of the star's surface is higher than that of the Sun.
D)   The star is moving away from Earth.

Question 14

The orbits of electrons in an atom are sometimes compared to the orbits of the planets around the Sun. However, only one of these characteristics of electron orbits is shared with planetary orbits. Which one?

Accepted Answer

A)   Larger orbits are associated with higher energies.
B)   The particle motions must be described by quantum mechanics.
C)   Only certain allowed orbits exist with certain allowed energies and allowed distances.
D)   The orbiting particles exhibit both particle and wave properties.

Question 15

Which of these properties of the isotopes 15N (nitrogen)  and 15O (oxygen)  are very nearly the same?

Accepted Answer

A)   number of protons in the nucleus
B)   number of neutrons in the nucleus
C)   nuclear mass and number of neutrons in the nucleus
D)   nuclear mass

Question 16

A spectrograph is a scientific instrument that

Accepted Answer

A)   measures the effectiveness of the specular reflection of mirrors.
B)   spreads out light from a source into its component colors, or spectrum.
C)   measures the transparency of different types of glass at different colors by using glass prisms.
D)   focuses all the colors of light from a star at one point so that the total intensity of the star can be measured, for photometry.

Question 17

According to modern atomic theory, light emitted by atoms originates from

Accepted Answer

A)   photons emitted directly from the nucleus.
B)   transitions of electrons between electron levels of the same atom.
C)   collisions between atoms.
D)   electrons emitted from the nucleus.

Question 18

An ionized hydrogen atom is simply a(n)

Accepted Answer

A)   proton.
B)   helium nucleus.
C)   neutron.
D)   electron.

Question 19

Consider a set of electrons undergoing transitions between energy levels. In the resulting bright line spectrum, the line with the shortest wavelength is produced by the transitions between which of these states?

Accepted Answer

A)   highest to middle
B)   highest to lowest
C)   lowest to highest
D)   middle to lowest

Question 20

The star P Cygni (in the constellation Cygnus, the Swan)  is surrounded by an extensive low-density atmosphere. It has a bright, continuous spectrum with many narrow, dark absorption lines and a few bright emission lines. The dark absorption lines are produced by

Accepted Answer

A)   the part of the low-density atmosphere that is between Earth and the surface of the star.
B)   the hot, low-density atmosphere of the star emitting light in all directions.
C)   all parts of the star, the stellar surface, and the atmosphere, equally.
D)   the hot, dense, opaque gas of the star's surface.

Exam 4: Atomic Physics and Spectra

A spectrograph is a scientific instrument that

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An astronomer measures the spectrum of a star and finds a spectral line at 499 nm wavelength. In the laboratory, this spectral line occurs at 500 nm. According to the Doppler effect, this object is moving _____ Earth at _____the speed of light.

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The mass of the electrically neutral particle, the neutron, which is one component of the atomic nucleus along with the proton, is _____ the mass of the proton.

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An ionized hydrogen atom is simply a(n)

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Which of these properties of the isotopes 15N (nitrogen) and 15O (oxygen) are very nearly the same?

Correct AnswerverifiedShow Answer

The range of temperatures in the Kelvin (absolute) scale between the freezing point and boiling point of water is

Correct AnswerverifiedShow Answer

The energy flux, F, emitted by a star is the amount of

Correct AnswerverifiedShow Answer

How many electrons surround the nucleus of a triply ionized magnesium atom, Mg IV? The atomic number of magnesium is 12.

Correct AnswerverifiedShow Answer

Consider a set of electrons undergoing transitions between energy levels. In the resulting bright line spectrum, the line with the shortest wavelength is produced by the transitions between which of these states?

Correct AnswerverifiedShow Answer

O III is

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Interstellar space (the space between the stars) is filled with extremely low-density hydrogen gas. In the vicinity of a hot star, this gas can be heated to a very high temperature. This hot, low-density gas will

Correct AnswerverifiedShow Answer

Ionization of an atom occurs when

Correct AnswerverifiedShow Answer

According to modern atomic theory, light emitted by atoms originates from

Correct AnswerverifiedShow Answer

The Sun's spectrum peaks in the yellow-green region (i.e., this region is the most intense part of its spectrum) . The spectrum of Rigel (the star in the knee of Rigel) peaks in the short-wavelength end of the visible spectrum. Compared with the Sun, Rigel is

Correct AnswerverifiedShow Answer

The spectrum of a star shows a set of dark absorption lines equivalent to the absorption lines of the Sun but with one exception: Every line appears at a slightly longer wavelength, shifted toward the red end of the spectrum. What conclusion can be drawn from this observation?

Correct AnswerverifiedShow Answer

The Kelvin scale measures

Correct AnswerverifiedShow Answer

The star P Cygni (in the constellation Cygnus, the Swan) is surrounded by an extensive low-density atmosphere. It has a bright, continuous spectrum with many narrow, dark absorption lines and a few bright emission lines. The dark absorption lines are produced by

Correct AnswerverifiedShow Answer

The Lyman series of ultraviolet spectral emission lines from hydrogen gas is produced by electrons jumping

Correct AnswerverifiedShow Answer

The orbits of electrons in an atom are sometimes compared to the orbits of the planets around the Sun. However, only one of these characteristics of electron orbits is shared with planetary orbits. Which one?

Correct AnswerverifiedShow Answer

If light from a hot, dense star passes through a cool cloud of gas,

Correct AnswerverifiedShow Answer

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An astronomer measures the spectrum of a star and finds a spectral line at 499 nm wavelength. In the laboratory, this spectral line occurs at 500 nm. According to the Doppler effect, this object is moving _ Earth at _the speed of light.

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Which of these properties of the isotopes ¹⁵N (nitrogen) and ¹⁵O (oxygen) are very nearly the same?

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