Question 1

At visible wavelengths, what type of intensity distribution does one see at the edge or limb of the Sun?

Accepted Answer

A) an image of uniform brightness right to the limb 
B) an image with uniform distribution except where active regions occur 
C) limb darkening 
D) limb brightening 
A) an image of uniform brightness right to the limb 
B) an image with uniform distribution except where active regions occur 
C) limb darkening 
D) limb brightening

Question 2

A coronal hole shows up most prominently in photographs taken at what wavelengths?

Accepted Answer

A) radio wavelengths 
B) visible light 
C) x ray 
D) the specific color of the first Balmer line of hydrogen, $\alpha$ , at 656.3 nm 
A) radio wavelengths 
B) visible light 
C) x ray 
D) the specific color of the first Balmer line of hydrogen, $\alpha$ , at 656.3 nm

Question 3

If the temperature near the center of a particular sunspot is 4350 K and the temperature of the surrounding photosphere is 5800 K, then the energy flux (energy passing through each m2/s) from the center of the sunspot is what fraction of the energy flux from the surrounding photosphere?

Accepted Answer

A) 75% 
B) 87% 
C) 56% 
D) 32% 
A) 75% 
B) 87% 
C) 56% 
D) 32%

Question 4

Thermonuclear fusion reactions in the core of the Sun convert four hydrogen nuclei into one helium nucleus. The helium nucleus has:

Accepted Answer

A) less mass than the four hydrogen nuclei, the lost mass becoming energy in an amount given by E = mc2. 
B) the same mass as the four hydrogen nuclei, because the mass of any product has to equal the mass of the sum of its parts by the law of conservation of matter. 
C) an undetermined amount of mass that depends on the temperature at which the reaction occurs. 
D) more mass than the four hydrogen nuclei, because energy is produced in the reaction, and this energy adds the extra mass, m = E/c2. 
A) less mass than the four hydrogen nuclei, the lost mass becoming energy in an amount given by E = mc2. 
B) the same mass as the four hydrogen nuclei, because the mass of any product has to equal the mass of the sum of its parts by the law of conservation of matter. 
C) an undetermined amount of mass that depends on the temperature at which the reaction occurs. 
D) more mass than the four hydrogen nuclei, because energy is produced in the reaction, and this energy adds the extra mass, m = E/c2.

Question 5

The dark lines in the solar spectrum are caused by:

Accepted Answer

A) places in the spectrum that would ordinarily be filled in by elements that are not present on the Sun. 
B) wavelengths that have been Doppler shifted to higher frequencies beyond the visible spectrum. 
C) wavelengths that have been Doppler shifted to lower frequencies beyond the visible spectrum. 
D) wavelengths that have been absorbed by atoms between us and the source of the light. 
A) places in the spectrum that would ordinarily be filled in by elements that are not present on the Sun. 
B) wavelengths that have been Doppler shifted to higher frequencies beyond the visible spectrum. 
C) wavelengths that have been Doppler shifted to lower frequencies beyond the visible spectrum. 
D) wavelengths that have been absorbed by atoms between us and the source of the light.

Question 6

Material in solar spicules is ejected out of the Sun at typical speeds of 20 km/s. What would be the observed wavelength of the Balmer H $\alpha$ hydrogen spectral line emitted by this gas, compared to that from stationary solar material?

Accepted Answer

A) There will be no shift, because the light is emitted by hydrogen gas in both the spicule and the stationary solar material. 
B) 0.000067 nm shorter than the H $\alpha$ from the stationary solar material 
C) 0.044 nm longer than the H $\alpha$ from stationary solar material 
D) 0.044 nm shorter than the H $\alpha$ from stationary solar material 
A) There will be no shift, because the light is emitted by hydrogen gas in both the spicule and the stationary solar material. 
B) 0.000067 nm shorter than the H $\alpha$ from the stationary solar material 
C) 0.044 nm longer than the H $\alpha$ from stationary solar material 
D) 0.044 nm shorter than the H $\alpha$ from stationary solar material

Question 7

What is the character of the sunspot cycle?

Accepted Answer

A) Sunspots increase and decrease in number over 11 years within a band of solar latitude between 10° and 30°, with no discernible dependence of sunspot latitude upon time. 
B) Starting at sunspot minimum, new spots appear uniformly over the Sun but gradually, new spots become concentrated at mid-latitudes as they increase and then decrease in number. 
C) Starting at sunspot minimum, new spots appear close to the equator, followed by newer spots farther from the equator until, when numbers decrease, they grow and decay at high latitudes. 
D) Starting at sunspot minimum, spots first appear far from the equator, followed by new spots appearing successively closer to the equator as they increase in number and finally, spots form close to the equator as numbers begin to decrease. 
A) Sunspots increase and decrease in number over 11 years within a band of solar latitude between 10° and 30°, with no discernible dependence of sunspot latitude upon time. 
B) Starting at sunspot minimum, new spots appear uniformly over the Sun but gradually, new spots become concentrated at mid-latitudes as they increase and then decrease in number. 
C) Starting at sunspot minimum, new spots appear close to the equator, followed by newer spots farther from the equator until, when numbers decrease, they grow and decay at high latitudes. 
D) Starting at sunspot minimum, spots first appear far from the equator, followed by new spots appearing successively closer to the equator as they increase in number and finally, spots form close to the equator as numbers begin to decrease.

Question 8

The time taken for neutrinos generated in the thermonuclear reactions at the center of the Sun to escape from its surface is:

Accepted Answer

A) about 170,000 years, just like the electromagnetic energy. 
B) about 1 million years. 
C) extremely short-a small fraction of a second-because they travel faster than the speed of light. 
D) a few seconds. 
A) about 170,000 years, just like the electromagnetic energy. 
B) about 1 million years. 
C) extremely short-a small fraction of a second-because they travel faster than the speed of light. 
D) a few seconds.

Question 9

The photosphere is the level of the Sun from which most of the visible radiation we see originates. The temperature of the base of the Sun's photosphere is roughly:

Accepted Answer

A) 600 K. 
B) 6000 K. 
C) 60,000 K. 
D) 1 million K. 
A) 600 K. 
B) 6000 K. 
C) 60,000 K. 
D) 1 million K.

Question 10

Virtually all of the Sun's mass is concentrated within what fraction of its radius?

Accepted Answer

A) the innermost 10% 
B) the innermost 30% 
C) the innermost 60% 
D) the outer 70% 
A) the innermost 10% 
B) the innermost 30% 
C) the innermost 60% 
D) the outer 70%

Question 11

The granulation pattern seen on the surface of the Sun results from:

Accepted Answer

A) heating of the photosphere by solar flares. 
B) the differential rotation of the Sun. 
C) strong magnetic fields cooling the gas in certain regions. 
D) convection of gas in the region under the photosphere. 
A) heating of the photosphere by solar flares. 
B) the differential rotation of the Sun. 
C) strong magnetic fields cooling the gas in certain regions. 
D) convection of gas in the region under the photosphere.

Question 12

How did astronomers first detect the high temperatures in the corona of the Sun?

Accepted Answer

A) by measuring the brightness of the corona in visible (white) light 
B) by direct measurements using space probes 
C) by observing emission lines of highly ionized elements like iron 
D) by observing the effects the high temperature has on Mercury and Venus 
A) by measuring the brightness of the corona in visible (white) light 
B) by direct measurements using space probes 
C) by observing emission lines of highly ionized elements like iron 
D) by observing the effects the high temperature has on Mercury and Venus

Question 13

How would you view the Sun's chromosphere?

Accepted Answer

A) You must wait for a total solar eclipse. 
B) You would use a filter that allows only the H $\alpha$ line to pass through. 
C) You would use a filter that allows everything except the H $\alpha$ line to pass through. 
D) You would take a broad-spectrum image (without a filter) from above Earth's atmosphere. 
A) You must wait for a total solar eclipse. 
B) You would use a filter that allows only the H $\alpha$ line to pass through. 
C) You would use a filter that allows everything except the H $\alpha$ line to pass through. 
D) You would take a broad-spectrum image (without a filter) from above Earth's atmosphere.

Question 14

If the temperature of the surface of the Sun doubled, the amount of energy we would receive would:

Accepted Answer

A) remain the same. 
B) double. 
C) increase by a factor of four. 
D) increase by a factor of 16. 
A) remain the same. 
B) double. 
C) increase by a factor of four. 
D) increase by a factor of 16.

Question 15

If the magnetic polarity of the north pole of the Sun at a particular time is north, what will be the polarity of the preceding or leading spot of a bipolar sunspot region rotating about the Sun in the northern hemisphere?

Accepted Answer

A) The polarity will depend upon the latitude of the spot and will be north if greater than 60° latitude and south if less than 60° latitude. 
B) It is not possible to determine this from the information given. 
C) It is south. 
D) It is north. 
A) The polarity will depend upon the latitude of the spot and will be north if greater than 60° latitude and south if less than 60° latitude. 
B) It is not possible to determine this from the information given. 
C) It is south. 
D) It is north.

Question 16

How do the physical conditions within a coronal hole compare with those of the rest of the solar corona?

Accepted Answer

A) higher temperature but very low density 
B) lower temperature but very high density 
C) higher temperature and higher density 
D) lower temperature and lower density 
A) higher temperature but very low density 
B) lower temperature but very high density 
C) higher temperature and higher density 
D) lower temperature and lower density

Question 17

The 11-year sunspot cycle on the Sun is:

Accepted Answer

A) the regular movement of a relatively constant number of sunspots from the poles to the equator of the Sun over an 11-year period. 
B) an irregular, sometimes absent variation in the number of visible sunspots. 
C) a perfectly regular buildup and decay of the number of sunspots, with a precise period of 11.1 years. 
D) a somewhat irregular but always present cycle of buildup and decay of sunspot numbers. 
A) the regular movement of a relatively constant number of sunspots from the poles to the equator of the Sun over an 11-year period. 
B) an irregular, sometimes absent variation in the number of visible sunspots. 
C) a perfectly regular buildup and decay of the number of sunspots, with a precise period of 11.1 years. 
D) a somewhat irregular but always present cycle of buildup and decay of sunspot numbers.

Question 18

Solar sound waves:

Accepted Answer

A) are the mechanism by which most solar energy is transported to the surface from the interior. 
B) are generated in the Sun's core by the violent nuclear activity there and move outward through the solar surface into space. 
C) reflect back and forth between the solar surface and layers deep in the solar interior. 
D) reach Earth, are picked up by sensitive sound detection equipment here, and are analyzed to give us important information about the solar interior. 
A) are the mechanism by which most solar energy is transported to the surface from the interior. 
B) are generated in the Sun's core by the violent nuclear activity there and move outward through the solar surface into space. 
C) reflect back and forth between the solar surface and layers deep in the solar interior. 
D) reach Earth, are picked up by sensitive sound detection equipment here, and are analyzed to give us important information about the solar interior.

Question 19

Due to differential rotation, sunspot groups near the north and south poles of the Sun may take as much as __________ to rotate around the Sun.

Accepted Answer

A) 5 days longer 
B) 10 days longer 
C) 5 days less 
D) 10 days less 
A) 5 days longer 
B) 10 days longer 
C) 5 days less 
D) 10 days less

Question 20

How much hydrogen is converted into helium and energy in the Sun each second?

Accepted Answer

A) 600 million tons 
B) 6 billion tons 
C) 600 tons 
D) 6 tons 
A) 600 million tons 
B) 6 billion tons 
C) 600 tons 
D) 6 tons

Exam 16: Our Star, the Sun

At visible wavelengths, what type of intensity distribution does one see at the edge or limb of the Sun?

A coronal hole shows up most prominently in photographs taken at what wavelengths?

If the temperature near the center of a particular sunspot is 4350 K and the temperature of the surrounding photosphere is 5800 K, then the energy flux (energy passing through each m2/s) from the center of the sunspot is what fraction of the energy flux from the surrounding photosphere?

Thermonuclear fusion reactions in the core of the Sun convert four hydrogen nuclei into one helium nucleus. The helium nucleus has:

The dark lines in the solar spectrum are caused by:

Material in solar spicules is ejected out of the Sun at typical speeds of 20 km/s. What would be the observed wavelength of the Balmer H α\alphaα hydrogen spectral line emitted by this gas, compared to that from stationary solar material?

What is the character of the sunspot cycle?

The time taken for neutrinos generated in the thermonuclear reactions at the center of the Sun to escape from its surface is:

The photosphere is the level of the Sun from which most of the visible radiation we see originates. The temperature of the base of the Sun's photosphere is roughly:

Virtually all of the Sun's mass is concentrated within what fraction of its radius?

The granulation pattern seen on the surface of the Sun results from:

How did astronomers first detect the high temperatures in the corona of the Sun?

How would you view the Sun's chromosphere?

If the temperature of the surface of the Sun doubled, the amount of energy we would receive would:

If the magnetic polarity of the north pole of the Sun at a particular time is north, what will be the polarity of the preceding or leading spot of a bipolar sunspot region rotating about the Sun in the northern hemisphere?

How do the physical conditions within a coronal hole compare with those of the rest of the solar corona?

The 11-year sunspot cycle on the Sun is:

Solar sound waves:

Due to differential rotation, sunspot groups near the north and south poles of the Sun may take as much as __________ to rotate around the Sun.

How much hydrogen is converted into helium and energy in the Sun each second?

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

Filters

If the temperature near the center of a particular sunspot is 4350 K and the temperature of the surrounding photosphere is 5800 K, then the energy flux (energy passing through each m²/s) from the center of the sunspot is what fraction of the energy flux from the surrounding photosphere?

Material in solar spicules is ejected out of the Sun at typical speeds of 20 km/s. What would be the observed wavelength of the Balmer H $\alpha$ hydrogen spectral line emitted by this gas, compared to that from stationary solar material?