AST 1002 Homework 5

Earth's magnetosphere is the A) region beyond Earth's atmosphere where Earth's magnetic field protects us from the solar wind. B) region in Earth's crust near each magnetic pole. C) molten core of Earth, whose motions produce the magnetic field. D) atmospheric layer between the stratosphere and thermosphere where motions are governed by Earth's magnetic field.

A) region beyond Earth's atmosphere where Earth's magnetic field protects us from the solar wind.

What are the major layers of Earth's atmosphere in the correct order from the surface upward? A) troposphere, stratosphere, mesosphere, thermosphere B) thermosphere, mesosphere, troposphere, stratosphere C) mesosphere, troposphere, thermosphere, stratosphere D) stratosphere, mesosphere, thermosphere, troposphere

A) troposphere, stratosphere, mesosphere, thermosphere

What are the Van Allen belts? A) two doughnut-shaped regions of high-energy charged particles in Earth's magnetosphere B) oval-shaped region around each of Earth's magnetic poles where charged particles collide with ions in Earth's atmosphere C) inner and outer parts of the asteroid belt D) regions of high concentration of electrons and ionized atoms in Earth's upper atmosphere where radio waves are reflected toward the surface of Earth

A) two doughnut-shaped regions of high-energy charged particles in Earth's magnetosphere

Most of Earth's earthquakes occur A) where crustal plates are colliding, separating, or sliding past one another. B) only where crustal plates are colliding head-on. C) only where crustal plates are sliding past each other, as in the San Andreas fault. D) more or less evenly over the entire Earth's surface.

A) where crustal plates are colliding, separating, or sliding past one another.

How has the CO2 concentration in Earth's atmosphere changed over the past thousand years? A) We have no means of measuring the CO2 concentration in Earth's atmosphere for times so far past. B) The CO2 concentration has remained absolutely constant. C) The CO2 concentration has increased steadily. D) The CO2 concentration was relatively constant for about 800 years but has increased significantly since 1800 A.D.

D) The CO2 concentration was relatively constant for about 800 years but has increased significantly since 1800 A.D.

We have found that the upper layers of the mantle are "plastic." Why is this important? A) Plastic is an important resource for the future. B) These layers can easily crack to allow pent-up heat and energy to escape. C) These layers can easily bend to accommodate oceans and mountains. D) The continents are able to float and drift on these layers.

D) The continents are able to float and drift on these layers.

Earth's thermosphere is the A) layer of molten iron and nickel below the mantle. B) region of the magnetosphere in which trapped high-energy charged particles spiral along magnetic field lines. C) intermediate atmospheric layer in which ultraviolet light from the Sun is absorbed by ozone (O3) molecules. D) outermost atmospheric layer in which ultraviolet light from the Sun ionizes atoms.

D) outermost atmospheric layer in which ultraviolet light from the Sun ionizes atoms.

Photosynthesis in plants on Earth maintains a balance between which of the two atmospheric gases? A) carbon dioxide and water vapor B) oxygen and water vapor C) nitrogen and oxygen D) oxygen and carbon dioxide

D) oxygen and carbon dioxide

In which layer of Earth's atmosphere does weather occur? A) stratosphere B) mesosphere C) thermosphere D) troposphere

D) troposphere

The Mid-Atlantic Ridge is being produced by A) the weight of the Atlantic Ocean on the thin seabed. B) tidal flows of ocean water meeting in the mid-Atlantic. C) two tectonic plates pushing together, producing upthrust. D) two tectonic plates moving apart because of volcanic upflow.

D) two tectonic plates moving apart because of volcanic upflow.

What is the ratio of nitrogen to oxygen in Earth's atmosphere? A) 1 part nitrogen to 2 parts oxygen B) 4 parts nitrogen to 1 part oxygen C) 1 part nitrogen to 4 parts oxygen D) equal parts nitrogen and oxygen

B) 4 parts nitrogen to 1 part oxygen

What causes the phenomenon of the aurora? A) Solar ultraviolet light excites ozone molecules in the ozone layer. B) Charged particles from the magnetosphere strike atoms in the upper atmosphere, causing them to emit characteristic colors of light. C) Light from solar flares reflects from high-altitude clouds in Earth's atmosphere. D) Charged particles emit light as they spiral along magnetic field lines in the magnetosphere.

B) Charged particles from the magnetosphere strike atoms in the upper atmosphere, causing them to emit characteristic colors of light.

What is the current status of Earth's ozone layer? A) The ozone layer has become too thick and is moving downward toward the surface, where its heating qualities contribute to global warming. B) The ozone layer has been somewhat depleted, but if left alone, it could restore itself in a century. C) The ozone layer has been distorted—too thin at the poles and too thick over the equatorial regions. D) The ozone layer is being irreversibly depleted and will probably disappear entirely within the next 200 years.

B) The ozone layer has been somewhat depleted, but if left alone, it could restore itself in a century.

What were the dominant gases in Earth's second atmosphere? A) nitrogen and oxygen B) carbon dioxide and nitrogen C) methane and ammonia D) hydrogen and helium

B) carbon dioxide and nitrogen

The Rocky Mountains of North America were formed by A) an ancient, mid-oceanic volcanic ridge now uplifted to become dry land. B) folding of Earth's crust where two crustal plates collided along a subduction zone. C) asteroid impacts during the first billion years of Earth's history. D) shrinking and folding of Earth's crust as Earth cooled and contracted.

B) folding of Earth's crust where two crustal plates collided along a subduction zone.

Ozone is a gas consisting of A) ionized oxygen atoms, positively charged. B) molecules containing three oxygen atoms. C) a mixture of several chlorofluorocarbon gases (CFCs). D) molecules containing combinations of oxygen and nitrogen atoms and electrons.

B) molecules containing three oxygen atoms.

Which is the most abundant gas in Earth's atmosphere? A) oxygen B) nitrogen C) hydrogen D) carbon dioxide

B) nitrogen

Why is the core of Earth made up predominantly of the heavy element iron? A) Chemical processes refined iron from iron oxides and other compounds in primordial rocks at the high temperatures of Earth's core, similar to present-day iron ore processing. B) Nuclear reactions in the very hot early core of Earth produced iron from lighter elements by nuclear fusion. C) The heavy elements sank slowly to the center during early molten phases in Earth's geological history. D) The heavy elements came together first out of the primordial dust and gas to form the initial Earth because of their greater density and gravitational attraction, and this core then attracted lighter rocks to its surface.

C) The heavy elements sank slowly to the center during early molten phases in Earth's geological history.

An "ozone hole" is A) a permanent region of very low ozone content in the stratosphere centered over the South Pole that has been there for thousands of years; the resulting transparency to UV radiation accounts for the lack of life forms there. B) the name given to small pits or holes on the aluminum surface of an aircraft, etched by the corrosive ozone encountered in the stratosphere and requiring regular maintenance. C) a region of the stratosphere above the South Pole where ozone levels occasionally drop to very low levels. D) a region centered on the equator where ozone levels are always very low because of destruction by direct sunlight.

C) a region of the stratosphere above the South Pole where ozone levels occasionally drop to very low levels.

The supercontinent Pangaea is believed to have been A) a myth, part of the Atlantis legend. B) the first continent to rise from the sea, which broke up 200 million years ago. C) the result of a collision of continents, of a type that occurs roughly every 500 million years. D) the original surface of Earth, before the oceans formed.

C) the result of a collision of continents, of a type that occurs roughly every 500 million years.