Question 1

Studying a spectrum from a star can tell us a lot.All of the following statements are true except one.Which statement is not true?

Accepted Answer

A) The total amount of light in the spectrum tells us the star's radius. 
B) The peak of the star's thermal emission tells us its temperature: hotter stars peak at shorter (bluer)wavelengths. 
C) We can identify chemical elements present in the star by recognizing patterns of spectral lines that correspond to particular chemicals. 
D) Shifts in the wavelengths of spectral lines compared to the wavelengths of those same lines measured in a laboratory on Earth can tell us the star's speed toward or away from us. 
A) The total amount of light in the spectrum tells us the star's radius. 
B) The peak of the star's thermal emission tells us its temperature: hotter stars peak at shorter (bluer)wavelengths. 
C) We can identify chemical elements present in the star by recognizing patterns of spectral lines that correspond to particular chemicals. 
D) Shifts in the wavelengths of spectral lines compared to the wavelengths of those same lines measured in a laboratory on Earth can tell us the star's speed toward or away from us.

Question 2

Laboratory measurements show hydrogen produces a spectral line at a wavelength of 486.1 nanometers (nm).A particular star's spectrum shows the same hydrogen line at a wavelength of 486.0 nm.What can we conclude?

Accepted Answer

A) The star is moving away from us. 
B) The star is getting hotter. 
C) The star is moving toward us. 
D) The star is getting colder. 
A) The star is moving away from us. 
B) The star is getting hotter. 
C) The star is moving toward us. 
D) The star is getting colder.

Question 3

We can see each other in the classroom right now because we

Accepted Answer

A) emit thermal radiation. 
B) emit visible light. 
C) emit infrared light. 
D) reflect visible light. 
E) reflect infrared light. 
A) emit thermal radiation. 
B) emit visible light. 
C) emit infrared light. 
D) reflect visible light. 
E) reflect infrared light.

Question 4

Visible light from a distant star can be spread into a spectrum by using a glass prism or

Accepted Answer

A) a diffraction grating. 
B) adaptive optics. 
C) a telescope. 
D) a flat glass mirror. 
A) a diffraction grating. 
B) adaptive optics. 
C) a telescope. 
D) a flat glass mirror.

Question 5

The atomic nuclei of the same element always have the same number of neutrons.

Accepted Answer

A) True 
 B)False

Question 6

The most common isotope of uranium is U-238,but the form used in nuclear bombs and nuclear power plants is U-235.Given that uranium has atomic number 92,how many neutrons are in each of these two isotopes?

Accepted Answer

U-238 has 146 neutro

Question 7

Which of the following best describes why we say that light is an electromagnetic wave?

Accepted Answer

A) Light can be produced only by electric or magnetic appliances. 
B) Light is produced only when massive fields of electric and magnetic energy collide with one another. 
C) The passage of a light wave can cause electrically charged particles to move up and down. 
D) The term electromagnetic wave arose for historical reasons,but we now know that light has nothing to do with either electricity or magnetism. 
A) Light can be produced only by electric or magnetic appliances. 
B) Light is produced only when massive fields of electric and magnetic energy collide with one another. 
C) The passage of a light wave can cause electrically charged particles to move up and down. 
D) The term electromagnetic wave arose for historical reasons,but we now know that light has nothing to do with either electricity or magnetism.

Question 8

Oxygen has atomic number 8.How many times must an oxygen atom be ionized to create an O⁺⁵ ion,and how many electrons will the ion have?

Accepted Answer

A) It must be ionized three times;it now has five electrons. 
B) It must be ionized five times;it now has five electrons. 
C) It must be ionized five times;it now has three electrons. 
D) It doesn't have to be ionized;it just needs to gain five protons. 
E) It doesn't have to be ionized;it already has only three electrons. 
A) It must be ionized three times;it now has five electrons. 
B) It must be ionized five times;it now has five electrons. 
C) It must be ionized five times;it now has three electrons. 
D) It doesn't have to be ionized;it just needs to gain five protons. 
E) It doesn't have to be ionized;it already has only three electrons.

Question 9

Thermal radiation is defined as

Accepted Answer

A) radiation with a spectrum whose shape depends only on the temperature of the emitting object. 
B) radiation produced by an extremely hot object. 
C) radiation that is felt as heat. 
D) radiation in the form of emission lines from an object. 
A) radiation with a spectrum whose shape depends only on the temperature of the emitting object. 
B) radiation produced by an extremely hot object. 
C) radiation that is felt as heat. 
D) radiation in the form of emission lines from an object.

Question 10

Each of the following describes an "Atom 1" and an "Atom 2." In which case are the two atoms different isotopes of the same element?

Accepted Answer

A) Atom 1: nucleus with 6 protons and 8 neutrons,surrounded by 6 electrons; Atom 2: nucleus with 7 protons and 8 neutrons,surrounded by 7 electrons. 
B) Atom 1: nucleus with 7 protons and 8 neutrons,surrounded by 7 electrons; Atom 2: nucleus with 7 protons and 7 neutrons,surrounded by 7 electrons. 
C) Atom 1: nucleus with 8 protons and 8 neutrons,surrounded by 8 electrons; Atom 2: nucleus with 8 protons and 8 neutrons,surrounded by 7 electrons. 
D) Atom 1: nucleus with 4 protons and 5 neutrons,surrounded by 4 electrons; Atom 2: nucleus with 5 protons and 5 neutrons,surrounded by 4 electrons. 
A) Atom 1: nucleus with 6 protons and 8 neutrons,surrounded by 6 electrons; Atom 2: nucleus with 7 protons and 8 neutrons,surrounded by 7 electrons. 
B) Atom 1: nucleus with 7 protons and 8 neutrons,surrounded by 7 electrons; Atom 2: nucleus with 7 protons and 7 neutrons,surrounded by 7 electrons. 
C) Atom 1: nucleus with 8 protons and 8 neutrons,surrounded by 8 electrons; Atom 2: nucleus with 8 protons and 8 neutrons,surrounded by 7 electrons. 
D) Atom 1: nucleus with 4 protons and 5 neutrons,surrounded by 4 electrons; Atom 2: nucleus with 5 protons and 5 neutrons,surrounded by 4 electrons.

Question 11

What is a compound?

Accepted Answer

A) a group of molecules 
B) a molecule containing hydrogen 
C) a molecule containing two or more elements 
D) an ionized molecule 
E) a molecule containing carbon 
A) a group of molecules 
B) a molecule containing hydrogen 
C) a molecule containing two or more elements 
D) an ionized molecule 
E) a molecule containing carbon

Question 12

You are currently emitting electromagnetic waves.

Accepted Answer

A) True 
 B)False

Question 13

How many atoms fit across the period at the end of this sentence?

Accepted Answer

A) hundreds 
B) thousands 
C) millions 
D) billions 
E) more than you could count in a lifetime 
A) hundreds 
B) thousands 
C) millions 
D) billions 
E) more than you could count in a lifetime

Question 14

All of the following statements about the Sun's corona are true.Which one explains why it is a source of X-rays?

Accepted Answer

A) The temperature of the corona's gas is some 1 to 2 million Kelvin. 
B) The corona lies above the visible surface of the Sun. 
C) The corona's gas consists mostly of hydrogen and helium. 
D) The corona's structure is largely shaped by magnetic fields. 
A) The temperature of the corona's gas is some 1 to 2 million Kelvin. 
B) The corona lies above the visible surface of the Sun. 
C) The corona's gas consists mostly of hydrogen and helium. 
D) The corona's structure is largely shaped by magnetic fields.

Question 15

Suppose you have a 100-watt light bulb that you leave turned on for one minute.How much energy does it use?

Accepted Answer

A) 6,000 joules 
B) 6,000 watts 
C) 100 watts 
D) 100 joules 
A) 6,000 joules 
B) 6,000 watts 
C) 100 watts 
D) 100 joules

Question 16

What is the difference between energy and power?

Accepted Answer

A) Power is the rate at which energy is used,so its units are a unit of energy divided by a unit of time. 
B) Power is measured in joules and energy is measured in watts. 
C) Power is used to describe energy of light,while the term energy has a broader meaning. 
D) There's no difference: Energy and power are different names for the same thing. 
A) Power is the rate at which energy is used,so its units are a unit of energy divided by a unit of time. 
B) Power is measured in joules and energy is measured in watts. 
C) Power is used to describe energy of light,while the term energy has a broader meaning. 
D) There's no difference: Energy and power are different names for the same thing.

Question 17

The shorter the wavelength of light,the higher its frequency.

Accepted Answer

A) True 
 B)False

Question 18

Grass appears green because

Accepted Answer

A) it emits green light and absorbs other colors. 
B) it absorbs green light and emits other colors. 
C) it transmits green light and emits other colors. 
D) it reflects green light and absorbs other colors. 
A) it emits green light and absorbs other colors. 
B) it absorbs green light and emits other colors. 
C) it transmits green light and emits other colors. 
D) it reflects green light and absorbs other colors.

Question 19

Vaporization is the process in which

Accepted Answer

A) molecules go from the solid phase to the liquid phase. 
B) molecules go from the liquid phase to the gas phase. 
C) molecules go directly from the solid phase to the gas phase. 
D) electrons are stripped from atoms. 
A) molecules go from the solid phase to the liquid phase. 
B) molecules go from the liquid phase to the gas phase. 
C) molecules go directly from the solid phase to the gas phase. 
D) electrons are stripped from atoms.

Question 20

Which of the following statements about thermal radiation is always true?

Accepted Answer

A) A hot object emits more radiation per unit surface area than a cool object. 
B) A cold object produces more total infrared and radio emission per unit surface area than a hot object. 
C) A hot object produces more total infrared emission than a cooler object. 
D) All the light emitted by hot object has higher energy than the light emitted by a cooler object. 
A) A hot object emits more radiation per unit surface area than a cool object. 
B) A cold object produces more total infrared and radio emission per unit surface area than a hot object. 
C) A hot object produces more total infrared emission than a cooler object. 
D) All the light emitted by hot object has higher energy than the light emitted by a cooler object.

Exam 5: Light and Matter: Reading Messages from the Cosmos

Studying a spectrum from a star can tell us a lot.All of the following statements are true except one.Which statement is not true?

Laboratory measurements show hydrogen produces a spectral line at a wavelength of 486.1 nanometers (nm).A particular star's spectrum shows the same hydrogen line at a wavelength of 486.0 nm.What can we conclude?

We can see each other in the classroom right now because we

Visible light from a distant star can be spread into a spectrum by using a glass prism or

The atomic nuclei of the same element always have the same number of neutrons.

The most common isotope of uranium is U-238,but the form used in nuclear bombs and nuclear power plants is U-235.Given that uranium has atomic number 92,how many neutrons are in each of these two isotopes?

Which of the following best describes why we say that light is an electromagnetic wave?

Oxygen has atomic number 8.How many times must an oxygen atom be ionized to create an O⁺⁵ ion,and how many electrons will the ion have?

Thermal radiation is defined as

Each of the following describes an "Atom 1" and an "Atom 2." In which case are the two atoms different isotopes of the same element?

What is a compound?

You are currently emitting electromagnetic waves.

How many atoms fit across the period at the end of this sentence?

All of the following statements about the Sun's corona are true.Which one explains why it is a source of X-rays?

Suppose you have a 100-watt light bulb that you leave turned on for one minute.How much energy does it use?

What is the difference between energy and power?

The shorter the wavelength of light,the higher its frequency.

Grass appears green because

Vaporization is the process in which

Which of the following statements about thermal radiation is always true?

A Modern View of the Universe

Discovering the Universe for Yourself

The Science of Astronomy

Making Sense of the Universe: Understanding Motion, Energy, and Gravity

Telescopes: Portals of Discovery

Our Planetary System

Formation of the Solar System

Planetary Geology: Earth and the Other Terrestrial Worlds

Planetary Atmospheres: Earth and the Other Terrestrial Worlds

Jovian Planet Systems

Asteroids, Comets, and Dwarf Planets: Their Nature, Orbits, and Impacts

Other Planetary Systems: The New Science of Distant Worlds

Our Star

Surveying the Stars

Star Birth

Star Stuff

The Bizarre Stellar Graveyard

Our Galaxy

Galaxies and the Foundations of Modern Cosmology

Galaxy Evolution

The Birth of the Universe

Dark Matter, Dark Energy, and the Fate of the Universe

Life in the Universe

Celestial Timekeeping and Navigation

Space and Time

Spacetime and Gravity

Building Blocks of the Universe

Filters