Question 1

Supergranules on the Sun are:

Accepted Answer

A) large and long-lived convecting gas cells, containing hundreds of ordinary granules. 
B) very large but otherwise ordinary granules. 
C) large areas in which the rapid convection of the gas destroys all granules that would otherwise form in that area. 
D) another name for large, long-lived sunspot groups. 
A) large and long-lived convecting gas cells, containing hundreds of ordinary granules. 
B) very large but otherwise ordinary granules. 
C) large areas in which the rapid convection of the gas destroys all granules that would otherwise form in that area. 
D) another name for large, long-lived sunspot groups. A

Question 2

At the maximum of the sunspot cycle most sunspots form around north and south latitude:

Accepted Answer

A) 0° (the Sun's equator). 
B) 15°. 
C) 30°. 
D) 90° (the solar poles). 
A) 0° (the Sun's equator). 
B) 15°. 
C) 30°. 
D) 90° (the solar poles). B

Question 3

The chemical composition of the surface layers of the Sun is determined primarily by:

Accepted Answer

A) examination of samples of meteorites that originated in the Sun. 
B) satellite measurements of the solar wind. 
C) theoretical modeling and computer calculation. 
D) spectroscopy. 
A) examination of samples of meteorites that originated in the Sun. 
B) satellite measurements of the solar wind. 
C) theoretical modeling and computer calculation. 
D) spectroscopy. D

Question 4

Solar sound waves are thought to travel:

Accepted Answer

A) only along the Sun's surface. 
B) only in the convective zone. 
C) only in the radiation zone. 
D) in both the convective and radiation zones. 
A) only along the Sun's surface. 
B) only in the convective zone. 
C) only in the radiation zone. 
D) in both the convective and radiation zones.

Question 5

Why does the observation of spectral emission from a highly ionized atom such as iron, Fe XIV, with 13 electrons missing, indicate very high gas temperatures?

Accepted Answer

A) The presence of iron means that nuclear fusion must be occurring, and this process needs very high temperatures. 
B) Highly ionized atoms must come from high-density regions that can only exist in high temperature gases. 
C) Collisions that remove this number of electrons must be very energetic between fast-moving atoms. 
D) Photons that will eject these electrons must be very energetic and come from high-temperature gas. 
A) The presence of iron means that nuclear fusion must be occurring, and this process needs very high temperatures. 
B) Highly ionized atoms must come from high-density regions that can only exist in high temperature gases. 
C) Collisions that remove this number of electrons must be very energetic between fast-moving atoms. 
D) Photons that will eject these electrons must be very energetic and come from high-temperature gas.

Question 6

The centers of the granular cells on the surface of the Sun are brighter than the edges of the cells because the centers are:

Accepted Answer

A) composed of different gases than the edges. 
B) hotter than the edges. 
C) denser than the edges. 
D) cooler than the edges. 
A) composed of different gases than the edges. 
B) hotter than the edges. 
C) denser than the edges. 
D) cooler than the edges.

Question 7

Fibrils in the Sun's atmosphere are also called:

Accepted Answer

A) sunspots. 
B) spicules. 
C) flares. 
D) granules. 
A) sunspots. 
B) spicules. 
C) flares. 
D) granules.

Question 8

The Sun emits light:

Accepted Answer

A) equally at all wavelengths (flat distribution). 
B) most intensely in the visible. 
C) most intensely in the infrared. 
D) most intensely in the radio spectrum. 
A) equally at all wavelengths (flat distribution). 
B) most intensely in the visible. 
C) most intensely in the infrared. 
D) most intensely in the radio spectrum.

Question 9

What is the cellular granulation pattern seen on the visible surface of the Sun?

Accepted Answer

A) The cells are regions of nuclear energy generation in the Sun's photosphere. 
B) The cells are the bases of circulation patterns that extend from the photosphere to the outer corona. 
C) Each cell is a region of stronger magnetic field that compresses and heats the gas within it. 
D) The cells are the tops of rising blobs of hot gas in the Sun's convective interior. 
A) The cells are regions of nuclear energy generation in the Sun's photosphere. 
B) The cells are the bases of circulation patterns that extend from the photosphere to the outer corona. 
C) Each cell is a region of stronger magnetic field that compresses and heats the gas within it. 
D) The cells are the tops of rising blobs of hot gas in the Sun's convective interior.

Question 10

What is a plage?

Accepted Answer

A) a bright area on the photosphere, seen in the light of helium and heavier atoms 
B) a bright area in the chromosphere, seen in the light of hydrogen and other atoms 
C) a sudden eruption on the photosphere in the vicinity of sunspot groups 
D) a region in the corona that looks bright against the darkness of space but dark against the brighter photosphere 
A) a bright area on the photosphere, seen in the light of helium and heavier atoms 
B) a bright area in the chromosphere, seen in the light of hydrogen and other atoms 
C) a sudden eruption on the photosphere in the vicinity of sunspot groups 
D) a region in the corona that looks bright against the darkness of space but dark against the brighter photosphere

Question 11

If the temperature at the edge of a solar granular cell is 5500 K and the center of the cell is 300 K hotter, what will be the ratio of fluxes of energy out of these two regions of the Sun (i.e., brightness contrast)?

Accepted Answer

A) center brighter than edge by a factor of 1.11 
B) center brighter than edge by a factor of 1.05 
C) edge brighter than center by a factor of 1.24 
D) center brighter than edge by a factor of 1.24 
A) center brighter than edge by a factor of 1.11 
B) center brighter than edge by a factor of 1.05 
C) edge brighter than center by a factor of 1.24 
D) center brighter than edge by a factor of 1.24

Question 12

Represented as a fraction of the solar radius, convection currents in the Sun's interior occupy what fraction of the Sun?

Accepted Answer

A) only about 1% of the radius 
B) the outer 29% of the radius 
C) only the inner 9% of the radius, at the core 
D) 100%, the whole radius 
A) only about 1% of the radius 
B) the outer 29% of the radius 
C) only the inner 9% of the radius, at the core 
D) 100%, the whole radius

Question 13

How many neutrinos pass through your outstretched hand (10 × 10 cm) from the Sun every second, day and night?

Accepted Answer

A) 1 trillion or 1012 
B) 1 trillion or 1012 in daytime-almost none during the night because they are stopped by Earth 
C) 10 billion or 1010 
D) only a few hundred, otherwise we would notice them 
A) 1 trillion or 1012 
B) 1 trillion or 1012 in daytime-almost none during the night because they are stopped by Earth 
C) 10 billion or 1010 
D) only a few hundred, otherwise we would notice them

Question 14

A positron is:

Accepted Answer

A) an antielectron, similar to a normal electron but with inverse properties, including a positive electrical charge. 
B) another name for a proton, or a positively charged hydrogen nucleus. 
C) a charged neutron. 
D) a positively charged neutrino, having positive charge and very small or zero mass. 
A) an antielectron, similar to a normal electron but with inverse properties, including a positive electrical charge. 
B) another name for a proton, or a positively charged hydrogen nucleus. 
C) a charged neutron. 
D) a positively charged neutrino, having positive charge and very small or zero mass.

Question 15

The visible light coming from the solar chromosphere is dominated by light at what wavelength(s)?

Accepted Answer

A) the red hydrogen Balmer H $\alpha$ emission line 
B) a continuous spectrum over all wavelengths, crossed by numerous dark absorption lines 
C) a featureless and continuous spectrum over all wavelengths from blue to red, scattered by chromospheric material 
D) the green emission line from iron atoms that have lost 13 electrons, Fe XIV 
A) the red hydrogen Balmer H $\alpha$ emission line 
B) a continuous spectrum over all wavelengths, crossed by numerous dark absorption lines 
C) a featureless and continuous spectrum over all wavelengths from blue to red, scattered by chromospheric material 
D) the green emission line from iron atoms that have lost 13 electrons, Fe XIV

Question 16

How do the low-frequency sound waves associated with the 5-minute oscillations traverse the interior of the Sun?

Accepted Answer

A) They move in straight lines from point to point but lose energy when they reach the solar surface. 
B) They move in straight lines from point to point and reflect from the underside of the surface, bouncing back and forth across the Sun. 
C) They follow curved paths through the interior and reflect from the underside of the solar surface. 
D) They follow curved paths through the interior but lose energy in raising the solar surface, disappearing when they reach the underside of the surface. 
A) They move in straight lines from point to point but lose energy when they reach the solar surface. 
B) They move in straight lines from point to point and reflect from the underside of the surface, bouncing back and forth across the Sun. 
C) They follow curved paths through the interior and reflect from the underside of the solar surface. 
D) They follow curved paths through the interior but lose energy in raising the solar surface, disappearing when they reach the underside of the surface.

Question 17

The photosphere is:

Accepted Answer

A) not very dense, and thus very transparent to visible light. 
B) very transparent to visible light because negative hydrogen ions absorb light and then re-emit it, thus sending it on its way. 
C) rather opaque to visible light because negative hydrogen ions absorb light. 
D) rather opaque to visible light because it is more dense than Earth's atmosphere. 
A) not very dense, and thus very transparent to visible light. 
B) very transparent to visible light because negative hydrogen ions absorb light and then re-emit it, thus sending it on its way. 
C) rather opaque to visible light because negative hydrogen ions absorb light. 
D) rather opaque to visible light because it is more dense than Earth's atmosphere.

Question 18

How much matter is converted into energy in the Sun each second?

Accepted Answer

A) 2 × 107 kg 
B) 4.2 × 109 kg 
C) 6.0 × 1011 kg 
D) 3.9 × 1026 kg 
A) 2 × 107 kg 
B) 4.2 × 109 kg 
C) 6.0 × 1011 kg 
D) 3.9 × 1026 kg

Question 19

The chlorine-argon neutrino detectors, like the one used by Davis, detect only neutrinos from a low-yield side branch of the main nuclear reaction in the Sun. Galium-germanium neutrino detectors were developed to detect neutrinos from the main nuclear reaction itself. When these detectors were used it was found that the:

Accepted Answer

A) measured neutrino flux was the originally predicted value-thus solving the solar neutrino problem. 
B) neutrino flux was still too low. 
C) neutrino flux was considerably higher than predicted, thus indicating a new solar neutrino problem. 
D) neutrinos being detected were not from the Sun at all but from other sources. 
A) measured neutrino flux was the originally predicted value-thus solving the solar neutrino problem. 
B) neutrino flux was still too low. 
C) neutrino flux was considerably higher than predicted, thus indicating a new solar neutrino problem. 
D) neutrinos being detected were not from the Sun at all but from other sources.

Question 20

The contraction of a star (or other object) due to its own gravity generates heat. If this process, known as the Kelvin-Helmholtz contraction, were to be the source of heat energy from the Sun, then the Sun's age:

Accepted Answer

A) would be about 10,000 years. 
B) would be about 1 billion years. 
C) would be about 25 million years. 
D) could easily be its present age of 4.5 billion years. 
A) would be about 10,000 years. 
B) would be about 1 billion years. 
C) would be about 25 million years. 
D) could easily be its present age of 4.5 billion years.

Exam 16: Our Star, the Sun

Supergranules on the Sun are:

At the maximum of the sunspot cycle most sunspots form around north and south latitude:

The chemical composition of the surface layers of the Sun is determined primarily by:

Solar sound waves are thought to travel:

Why does the observation of spectral emission from a highly ionized atom such as iron, Fe XIV, with 13 electrons missing, indicate very high gas temperatures?

The centers of the granular cells on the surface of the Sun are brighter than the edges of the cells because the centers are:

Fibrils in the Sun's atmosphere are also called:

The Sun emits light:

What is the cellular granulation pattern seen on the visible surface of the Sun?

What is a plage?

If the temperature at the edge of a solar granular cell is 5500 K and the center of the cell is 300 K hotter, what will be the ratio of fluxes of energy out of these two regions of the Sun (i.e., brightness contrast)?

Represented as a fraction of the solar radius, convection currents in the Sun's interior occupy what fraction of the Sun?

How many neutrinos pass through your outstretched hand (10 × 10 cm) from the Sun every second, day and night?

A positron is:

The visible light coming from the solar chromosphere is dominated by light at what wavelength(s)?

How do the low-frequency sound waves associated with the 5-minute oscillations traverse the interior of the Sun?

The photosphere is:

How much matter is converted into energy in the Sun each second?

The contraction of a star (or other object) due to its own gravity generates heat. If this process, known as the Kelvin-Helmholtz contraction, were to be the source of heat energy from the Sun, then the Sun's age:

Astronomy and the Universe

Knowing the Heavens

Eclipses and the Motion of the Moon

Gravitation and the Waltz of the Planets

The Nature of Light

Optics and Telescopes

Comparative Planetology I: Our Solar System

Comparative Planetology II: the Origin of Our Solar System

The Living Earth

Our Barren Moon

Mercury, Venus, and Mars: Terrestrial, yet Unique

Jupiter and Saturn: Lords of the Planets

Jupiter and Saturns Satellites of Fire and Ice

Uranus, Neptune, Pluto, and the Kuiper Belt: Remote Worlds

Asteroids, Comets, and Impacts

The Nature of the Stars

The Birth of Stars

Stellar Evolution: on and After the Main Sequence

Stellar Evolution: The Death of Stars

Stellar Remnants: Neutron Stars and Black Holes

Our Galaxy

Galaxies

Quasars and Active Galaxies

Cosmology: The Origin and Evolution of the Universe

Exploring the Early Universe

The Search for Extraterrestrial Life

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