PHSC 310 Ch. 16 Homework

The critical temperature the core must reach for a star to shine by fusion is: A) 10 million K. B) 127,000 K. C) 100 million K. D) 11,000 K. E) 5,800 K.

A) 10 million K.

The percentage (by number of atoms) of the Sun that is Hydrogen is about: A) 91%. B) 71%. C) 27%. D) 9%. E) less than 1%.

A) 91%.

In the proton-proton cycle, the helium atom and neutrino have less mass than the original hydrogen. What happens to the "lost" mass? A) It is converted to energy. B) It is transformed into electrons. C) It is recycled back into hydrogen. D) Conservation of mass dictates no mass can be lost. E) It is ejected into space.

A) It is converted to energy.

On the Sun, what takes approximately 22 years to happen? A) The complete sunspot cycle, including magnetic field reversals. B) The Sun takes that time to rotate on its axis. C) Solar vibrations begin every 22 years. D) The corona reaches its maximum temperature and ejects gas every 22 years. E) Solar activities goes from its maximum to minimum.

A) The complete sunspot cycle, including magnetic field reversals.

What is it about the Sun's corona that astronomers don't understand? A) The corona is much hotter than layers of the Sun that are closer to the solar interior. B) The corona seems to absorb 2/3 of the neutrinos that pass through it. C) During total solar eclipses, the corona sometimes disappears from view. D) No one knows why that part of the Sun's atmosphere does not drift away into space. E) The Sun's corona extends to the outer reaches of the solar system.

A) The corona is much hotter than layers of the Sun that are closer to the solar interior.

In the proton-proton cycle, the positron is: A) an anti-electron. B) a spin conservation particle. C) massless. D) intermediate between the proton and neutron in mass. E) the chief means energy reaches the photosphere.

A) an anti-electron.

There appears to be a correlation between the 22-year solar cycle and: A) droughts in North America. B) change of which political party has the majority in the U.S. Congress. C) the length of Mercury's day. D) the length of Saturn's year. E) asteroid impacts on Earth.

A) droughts in North America.

The pattern of rising hot gas cells all over the photosphere is called: A) granulation. B) convective projections. C) sunspots. D) prominences. E) filaments.

A) granulation.

What two energy transport mechanisms, in order from outside the core to the surface, are found in the Sun? A) radiative diffusion, convection B) radiative diffusion, conduction C) conduction, radiative diffusion D) convection, conduction E) conduction, convection

A) radiative diffusion, convection

From inside out, which is in the correct order for the structure of the Sun? A) radiative zone, convective zone, chromosphere B) photosphere, radiative zone, corona C) core, chromosphere, photosphere D) core, convective zone, radiative zone E) convective zone, radiative zone, granulation

A) radiative zone, convective zone, chromosphere

Suppose a large flare is detected optically. How long until radio interference arrives? A) simultaneously B) about 12 hours C) about four days D) 8.5 minutes later E) no relation between the two

A) simultaneously

The vibrations of the Sun reveal information about: A) the interior structure of the Sun. B) the magnetic field of the Sun. C) the structure of the atmosphere of the Sun. D) the temperature of the core of the Sun. E) the production of energy in the Sun.

A) the interior structure of the Sun.

The primary source of the Sun's energy is: A) the strong force fusing hydrogen into helium. B) oxidation of carbon in the core. C) dark energy. D) the weak force creating energy from uranium decay. E) gravitational collapse of the helium coreward.

A) the strong force fusing hydrogen into helium.

As the Sun rotates, an individual sunspot can be tracked across its face. From eastern to western limb, this takes about: A) two weeks. B) a week. C) 5.5 years. D) a month. E) 12 hours.

A) two weeks.

Which is the net result of the proton-proton chain? A) 6 protons = 2 heliums + 3 positrons + 3 neutrinos + gamma rays B) 4 protons = 1 helium 4 + 2 neutrinos + gamma rays C) 2 protons = deuterium + a positron + an antineutrino + X-rays D) 4 protons = 1 helium 4 + a positron + a neutrino + gamma rays E) 4 protons = 2 heliums 2 + 2 positrons + ultraviolet radiation

B) 4 protons = 1 helium 4 + 2 neutrinos + gamma rays

The percentage (by mass) of the Sun that is Hydrogen is about: A) 91%. B) 71%. C) 27%. D) 9%. E) less than 1%.

B) 71%.

Large circulation patterns in the Sun, dubbed "Conveyor Belts," transport material from the equator to the poles, then back to the equator at a depth of 300,000 km, take how long to complete a cycle? A) Less than a day B) A few decades C) A few years D) Tens of millions of years, comparable to the convection cycle in Earth's mantle E) A few centuries

B) A few decades

Stellar nurseries, such as the Orion nebula, contain hundreds or more fragmenting and contracting regions, as well as many protostars and stars. What condition would allow a protostar to become a stable star? A) Protostars do not become stable stars. B) When a protostar becomes hot enough for nuclear fusion to start, thermal pressure can balance the force of gravity. C) Eventually, a protostar will grow so large that it will stop fragmenting and start rotating.

B) When a protostar becomes hot enough for nuclear fusion to start, thermal pressure can balance the force of gravity.

How many planet Earths could fit inside the Sun? A) 110 B) a little over a million C) almost ten million D) close to a billion E) about a thousand

B) a little over a million

Which of these are NOT associated with the active Sun? A) aurora B) granulation C) flares D) prominences E) sunspots

B) granulation

During a period of high solar activity, the corona: A) becomes smooth and even. B) is more irregular. C) disappears. D) shrinks to half its normal size. E) cools almost to the temperature of the photosphere.

B) is more irregular.

Loops of glowing hydrogen seen hanging over the solar limb during totality are: A) flares. B) prominences. C) solar rainbows. D) filaments. E) haloes.

B) prominences.

The above diagram indicates that: (looks like a hill) A) the Sun is most dense somewhere between its surface and its core. B) the Sun is more dense at its core than at its surface. C) the Sun is least dense somewhere between its surface and its core. D) the Sun has about the same density throughout its interior. E) the Sun is more dense at its surface than at its core.

B) the Sun is more dense at its core than at its surface.

What is the size of a typical granule or convection cell seen in the photosphere? A) 1 km B) 10 km C) 1,000 km D) 10,000 km E) 100 km

C) 1,000 km

The percentage (by mass) of the Sun that is helium is about: A) 91%. B) 71%. C) 27%. D) 9%. E) less than 1%.

C) 27%.

How would sunspots appear if you could magically remove them from the Sun? A) They would shine only with reflected sunlight, appearing similar to Venus. B) They would appear blue-white, like Sirius but brighter. C) They would shine bright orange in color, like Arcturus. D) They would not appear any differently than on the surface of the Sun. E) Because sunspots are dark spots, they would be invisible against the blackness of space.

C) They would shine bright orange in color, like Arcturus.

How long does the sunspot cycle last, on average? A) about 76 years B) between 25 and 35 days C) about 11 years D) about seven years E) 365.25 days

C) about 11 years

By what mechanism does solar energy reach the Sun's photosphere from the layer just underneath it? A) conduction B) differentiation C) convection D) radiation E) ionization

C) convection

The solar winds blow outward from: A) the Sun's poles only. B) sunspots. C) coronal holes. D) the entire photosphere. E) flares.

C) coronal holes.

What natural barrier tries to prevent two protons from combining? A) antigravity B) the weak nuclear force C) electromagnetic repulsion D) dark energy E) the strong nuclear force

C) electromagnetic repulsion

Hydrostatic equilibrium in our Sun is the balance between: A) radiation and gravitation. B) convection and gravitation. C) gravitation and pressure. D) pressure and radiation. E) convection and radiation.

C) gravitation and pressure.

The light we see from the Sun comes from which layer? A) chromosphere B) troposphere C) photosphere D) corona E) ionosphere

C) photosphere

About what percent of the incoming energy from the Sun reaches Earth's surface? A) 60-80% B) 70-90% C) 30-60% D) 50-70% E) 80-100%

D) 50-70%

Why couldn't you stand on the Sun's surface? A) You could stand on it, if a sufficiently protective spacesuit could be designed. B) The Sun has no surface at all...the photosphere is an illusion. C) The Sun's surface is too highly magnetized for anything to survive there. D) The Sun doesn't have a solid surface. E) You could stand on the surface.

D) The Sun doesn't have a solid surface.

What would happen if the fusion rate in the core of the Sun were increased but the core could not expand? A) The Sun's core would start to cool down, and the rate of fusion would decrease. B) The Sun's core would reach a new equilibrium at a lower temperature. C) The Sun's core would reach a new equilibrium at a higher temperature. D) The Sun's core would start to heat up, and the rate of fusion would increase even more.

D) The Sun's core would start to heat up, and the rate of fusion would increase even more.

A loop of gas following the magnetic field lines between sunspots' poles is: A) a coronal hole. B) a coronal mass ejection. C) a flare. D) a prominence. E) a ray.

D) a prominence.

From where does most of the solar wind flow? A) flares B) sunspots C) prominences D) coronal holes E) granules

D) coronal holes

The number of sunspots and their activity peak about every: A) 76 years. B) six months. C) year. D) eleven years. E) 36 days.

D) eleven years.

The most striking example of solar variability was: A) the Dust Bowl drought of the 1930s. B) Joseph's seven lean years in the Old Testament. C) the Sporer Minimum that doomed the Anasazi. D) the Maunder Minimum from 1645-1715. E) the fall of Rome.

D) the Maunder Minimum from 1645-1715.

The solar constant is a measure of: A) the total energy emitted by the Sun in all directions. B) the energy received by the Sun at any location in the solar system. C) the energy received by the Sun on Earth's surface. D) the energy received by the Sun at the location of Earth. E) the energy emitted by the Sun at the photosphere.

D) the energy received by the Sun at the location of Earth.

The luminosity of the Sun is a measure of: A) the energy emitted by the Sun at the photosphere. B) the energy received by the Sun at the location of Earth. C) the energy received by the Sun on Earth's surface. D) the total energy emitted by the Sun in all directions. E) the energy received by the Sun at any location in the solar system.

D) the total energy emitted by the Sun in all directions.

The area in the Sun's atmosphere located above the chromosphere (1,500-10,000 km) where the temperature rises dramatically is called the: A) solar wind. B) photosphere. C) convection zone. D) transition zone. E) corona.

D) transition zone.

The standard solar model is a mathematical model that uses observational data and theoretical insights to describe the inner workings of the sun. Two key parameters used in the standard solar model are temperature and density. If we assume that the Sun is in hydrostatic equilibrium, the model predicts that the Sun's temperature should _______________ and its density should ______________ from its core to its surface. USE: Increase or Decrease

Decrease, Decrease

The speed of light is 3.00 × 108 m/s. If 2.00 kg of mass is converted to energy, how much energy will be produced? A) 6.00 × 108 J B) 9.00 × 1016 J C) 6.00 × 104 J D) 1.50 × 108 J E) 1.80 × 1017 J

E) 1.80 × 1017 J

The critical temperature to initiate the proton-proton cycle in the cores of stars is: A) 100 million K. B) 3,000 K. C) 2,300,000 K. D) 5,800 K. E) 10 million K.

E) 10 million K.

The temperature of the layer of gas that produces the visible light of the Sun is: A) 12,300 K. B) 3,500 K. C) 300,000 K. D) 15 million K. E) 5,800 K.

E) 5,800 K.

While observing the Sun, you note a large number of sunspots. What can you conclude? A) This is a period of low solar activity. B) Earth's climate will be unusually cold. C) The Sun is less luminous than usual. D) The Sun's rotation is slower than average. E) There are likely to be an above average number of flares and prominences.

E) There are likely to be an above average number of flares and prominences.

Sunspots are dark splotches on the Sun. Which statement is true? A) They are hotter than the surrounding areas of the Sun. B) They are extremely cold objects, as cold as Pluto. C) They are associated with areas of very low magnetic fields. D) They are solid bodies floating on the surface of the Sun. E) They are extremely hot, but cooler than the surrounding areas of the Sun.

E) They are extremely hot, but cooler than the surrounding areas of the Sun.

The Solar and Heliospheric Observatory (SOHO) is positioned: A) in a geosynchronous orbit around the Earth. B) in near-Earth orbit. C) on the far side of the Moon. D) on the far side of the Sun at the L3 Langrangian Point. E) about 1.5 million kilometers from Earth at the L1 Lagrangian Point.

E) about 1.5 million kilometers from Earth at the L1 Lagrangian Point.

Sunspots: A) are always found close to the Sun's poles. B) are relatively constant in number every year. C) travel over the surface of the Sun from pole to pole. D) were most numerous during the Maunder Minimum. E) come in pairs, representing the north and south magnetic fields.

E) come in pairs, representing the north and south magnetic fields.

Visible sunspots lie in the: A) transition zone. B) radiative zone. C) corona. D) chromosphere. E) granulation in the photosphere.

E) granulation in the photosphere.

The outward pressure of hot gas in the Sun: A) weakens the magnetic field. B) is responsible for variations in the sunspot cycle. C) is cooling the photosphere. D) is increasing the Sun's diameter. E) is balanced by the inward gravitational pressure.

E) is balanced by the inward gravitational pressure.

When we glimpse the chromosphere at the start and end of totality, its color is: A) green (the famous flash). B) yellow, like the photosphere below it. C) blue, due to the ionization of nitrogen by the magnetic fields. D) white from the moonlight. E) red, due to ionized hydrogen at lower pressure.

E) red, due to ionized hydrogen at lower pressure.

The density of the Sun is most similar to which object? A) the Earth B) Halley's Comet's nucleus C) the Moon E) Mercury F) Jupiter

F) Jupiter