chp 16

13. Which of the following particles has the lowest mass? a. a neutrino b. a proton c. a neutron d. an electron e. the nucleus of a hydrogen atom

a. a neutrino

27. When great currents of hot material rise inside the Sun (and cooler material sinks downward), energy is being transferred by a process known as: a. convection b. radiation c. conduction d. equilibrium e. politics

a. convection

5. Today we realize that the source of energy for the Sun is a process called a. nuclear fusion b. Kelvin-Helmholtz contraction c. mechanical to thermal energy conversion d. radioactivity e. dilithium crystal moderation

a. nuclear fusion

18. Where in the Sun does fusion of hydrogen occur? a. only in the core b. only near the photosphere (its visible surface layer) c. pretty much throughout the entire body of the Sun d. only in the layer where there is a lot of convection going on e. nowhere

a. only in the core

4. Physicists Kelvin and Helmholtz in the last century proposed that the source of the Sun's energy could be: a. radioactive rocks b. a slow contraction c. meteorites falling in d. the annihilation of antimatter e. nuclear fusion

b. a slow contraction

17. If the "fuel" for nuclear fusion is nuclei of hydrogen, and the Earth's oceans are filled with hydrogen atoms in water all being jostled together, why isn't there a lot of fusion happening in our oceans? a. the hydrogen in our oceans is the wrong type of hydrogen for fusion b. for hydrogen nuclei to fuse, they must get very close to each other, which the nuclei in the oceans cannot do c. for hydrogen to fuse, the nuclei must first join together in long chains of atoms d. on Earth, only hydrogen that is in deep mines under the Earth is far enough underground for fusion e. you can't fool me, hydrogen in the Earth's oceans does undergo fusion; that's what keeps our oceans warm

b. for hydrogen nuclei to fuse, they must get the oceans cannot do

24. What happens to the positron created during the p-p chain of nuclear reactions inside the Sun? a. it merges with a proton to become a deuterium (heavy hydrogen) nucleus b. it quickly collides with an electron and turns into gamma-ray energy c. it ultimately forms an anti-helium nucleus d. it turns quickly into a neutrino, which can escape from the Sun e. it just sits there at the core of the Sun for billions of years, unable to interact

b. it quickly collides with an electron and turns into gamma-ray energy

35. Which of the following is NOT an experiment that is searching for neutrinos coming from the Sun? a. looking for radioactive argon atoms in a tank of cleaning fluid deep in an underground mine b. looking for changes in the Doppler shift of lines in the atmosphere of the Sun c. looking for radioactive gallium in a vast quantity of ordinary gallium d. looking with sensitive light meters in a giant vat of pure water deep underground in Japan e. all of the above are ways to search for neutrinos

b. looking for changes in the Doppler shift of lines in the atmosphere of the Sun

28. When energy is first produced by fusion deep in the core of the star, that energy moves outward mostly by what process? a. convection b. radiation c. conduction d. theoretical modeling e. none of the above

b. radiation

31. Which of the following is a way for astronomers to learn more about the interior of the Sun? a. study the corona during eclipses of the Sun b. study the oscillations (pulsations) of the Sun's surface c. follow the orbit of Mercury, the closest planet to the Sun d. take photographs of the Sun in the light absorbed by hydrogen atoms e. study the accounts in ancient legends of the realm where the devil is supposed to live

b. study the oscillations (pulsations) of the Sun's surface

0. Which part of the Sun has the greatest density? a. the photosphere b. the core c. the convection region d. the corona e. you can't fool me; all the Sun's parts have the same density

b. the core

19. If it takes an average of 14 billion years before any proton inside the Sun will undergo fusion, and the Sun is only about 5 billion years old, why do astronomers believe that fusion is going on there now? a. fusion begins with particles even lighter than protons, which fuse more easily b. there are an enormous number of protons inside the Sun, and some of them will fuse much sooner than the average c. much more fusion takes place in the hot atmosphere of the Sun (where it can happen faster), not deep inside (where fusion is slow) d. most of the fusion inside the Sun involves carbon, not protons; carbon fuses much more quickly e. there is no fusion going on inside the Sun, and the fact given in the question is one of the reasons why

b. there are an enormous number of protons inside the Sun, and some of them will fuse much sooner than the average

36. Astronomers and physicists now believe they know what is happening to the missing neutrinos from the Sun (the neutrinos that our theories say should be emerging from the Sun, but our experiments in that underground mine could not find). These neutrinos are: a. not being produced by the Sun because our star's nuclear fusion period has ended b. turning into a different type of neutrino in a neutrino oscillation c. being converted to antimatter in the core of the Sun and being destroyed as they hit matter d. changing course before they reach the Earth as they hit other neutrinos in space e. all aimed at Bayonne, New Jersey, and our neutrino experiments are located elsewhere

b. turning into a different type of neutrino in a neutrino oscillation

6. According to the formula E=mc2, a. mass has to travel at the speed of light before it can produce any energy b. energy can travel much faster than light (in fact its speed can be the speed of light squared) c. a little bit of mass can be converted into a substantial amount of energy d. when two masses collide, we always get a lot of light e. Einstein was a male chauvinist twice over

c. a little bit of mass can be converted into a substantial amount of energy

23. Who pays the bill for the energy generated by nuclear fusion in the Sun? In other words, where does the energy pouring out of the Sun come from ultimately? a. the Sun is spinning more slowly as time goes on; rotation energy is lost b. heavy nuclei are breaking apart into lighter nuclei c. a little bit of mass is lost in each fusion reaction and is turned into energy (the Sun is losing mass) d. material (like meteorites) is falling into the Sun and being vaporized to produce energy e. American taxpayers pay this bill, as they do so many others!

c. a little bit of mass is lost in each fusion reaction and is turned into energy (the Sun is losing mass)

9. Which of the following, produced at the core of the Sun, will take the shortest time to emerge from the Sun's photosphere (surface)? a. a photon (wave) of gamma-rays b. a positron c. a neutrino d. a deuteron e. an x-ray produced after radiation has interacted with matter in the core

c. a neutrino

33. Which of the following statements about helioseismology experiments is FALSE: a. the pulsations these experiments measure take about an hour to emerge from the Sun's interior b. small changes in the velocity of the waves of pulsation coming from inside the Sun help astronomers figure out the structure of the Sun's interior c. helioseismology measures waves that are set up by the motion of neutrinos from the core of the Sun d. a typical pulsation takes about 5 minutes to complete a full cycle from maximum to minimum speed and back again e. Helioseismology allows astronomers to look under a sunspot and see how it works

c. helioseismology measures waves that are set up by the motion of neutrinos from the core of the Sun

25. The Sun is an enormous ball of gas. Left to itself, a ball of so many atoms should collapse under its own tremendous gravity. Why is our Sun not collapsing? a. the gravity of the planets around the Sun pulls its material outward, preventing collapse b. the pressure of the corona keeps the Sun's main body of gases confined to a small volume c. nuclear fusion in the core keeps the temperature and the pressure inside the Sun at a high enough level so that gravity is balanced d. neutrinos from the core exert an enormous pressure on the layers of the Sun as they travel outward; this pressure is more than enough to keep our star from collapsing e. you can't fool me, the Sun is shrinking all the time, it just happens very slowly

c. nuclear fusion in the core keeps the temperature and the pressure inside the Sun at a high enough level so that gravity is balanced

26. The material inside the Sun is in the form of a a. solid b. liquid c. plasma d. ball of iron atoms e. none of the above

c. plasma

8. Which of the following is NOT one of the fundamental particles that we find inside atoms? a. protons b. neutrons c. positrons d. electrons e. all four of the above are found in most atoms

c. positrons

15. When two light elements collide to undergo nuclear fusion, a. the total mass involved increases b. the positive charges in the nuclei attract, pulling the nuclei together faster and faster c. some of the energy in their mass is released d. only one survives; the other turns into a release of pure energy e. the result is always to make nuclei of iron

c. some of the energy in their mass is released

1. A friend (who does not have the new awareness which you have gained from this course) suggests that the mechanism that keeps the Sun shining as brightly as it does is the burning of coal. You brilliantly challenge his theory! Your challenge comes in several related steps; which of the following is one of those steps? a. we have found many more neutrinos than we expected in our underground experiments b. new protostars shine by gravitational collapse (the heat of clumping) c. the dating of radioactive rocks show that the Earth and thus the Sun are billions of years old d. most of the Sun is made of antimatter (which explodes when it touches matter) e. the C-N-O cycle can also produce helium

c. the dating of radioactive rocks show that the Earth and thus the Sun are billions of years old

14. The strongest force we know is a. gravity, which holds the Earth and the Sun together b. electricity, which pulls unlike charges together c. the nuclear force which holds nuclei together d. the attraction of Bayonne, New Jersey, for tourists e. none of the above

c. the nuclear force which holds nuclei together

12. A college friend of yours who has been postponing taking any science courses hears you talking about the generation of nuclear energy in the Sun and makes the following observation: "The whole idea of the atomic nucleus is pretty ridiculous. If an oxygen nucleus consists of eight protons and eight neutrons, the charge on that nucleus is positive. Since even I learned in high school that like charges repel, such a nucleus would find all its positive protons repelling and quickly fall apart." How would you answer his argument? a. gravity is much stronger than electric repulsion and holds every nucleus together b. the neutrons in the nucleus are negative, so they cancel the positive charge on the protons c. the nuclear force, which is attractive over short distances like the nucleus, and stronger than electricity, holds the nucleus together d. the electrons outside the nucleus repel the protons and keep them inside the nucleus e. there is no answer; scientists do not have a clue about how the nucleus manages to keep itself together

c. the nuclear force, which is attractive over short distances like the nucleus, and stronger than electricity, holds the nucleus together

20. The process of fusion that keeps our Sun shining begins with which building blocks? a. two electrons b. two deuterons c. two protons d. two Einsteinium nuclei e. two neutrinos

c. two protons

2. When did scientist begin to understand how the Sun produces all the energy that it does? a. Most of the process was already understood by the ancient Greeks b. Most of the process was understood by the end of the 18th century (the year 1800) c. Most of the process was understood by the end of the 19th century (the year 1900) d. The process was not well understood until the 1930's e. You can't fool me; astronomers still don't have a clue about how the Sun produces energy

d. The process was not well understood until the 1930's

22. At the end of the p-p chain of nuclear fusion in the Sun, hydrogen nuclei have been converted into: a. carbon nuclei b. heavy hydrogen nuclei c. antimatter and nothing else d. a helium nucleus e. a lithium nucleus

d. a helium nucleus

32. The Global Oscillations Network Group (GONG) Project is engaged in: a. measuring where earthquakes happen around the Earth by the waves they generate b. measuring the number of sunspots on the surface of the Sun at any given hour c. measuring the quality of the "seeing" (the "jiggling" of the Earth's atmosphere) at all the major observatories around the world d. measuring the pulsations of the Sun from stations around the world e. measuring how problems on the World Wide Web are affecting the communication among astronomers

d. measuring the pulsations of the Sun from stations around the world

9. The antimatter version of an electron is called a a. proton b. neutrino c. antitron d. positron e. gammatron

d. positron

11. Which of the following statements about antimatter is true ? a. antimatter is only a theory, we have no evidence that it exists b. antimatter only exists in Earth laboratories; it cannot be made in stars c. antimatter cannot be made in laboratories; we have tried but it just can't be done d. when a particle of matter and the corresponding particle of antimatter meet, they become pure energy e. our telescopes clearly see many nearby antimatter stars in the Milky Way galaxy

d. when a particle of matter and the corresponding particle of antimatter meet, they become pure energy

34. Which of the following best describes the first set of experiments, using chlorine traps, that were searching for electron neutrinos from the Sun? a. All the experiments had technical problems detecting neutrinos, which are very "antisocial" and thus very hard to catch b. The experiments worked OK, but they found no neutrinos at all; not a single one c. All the neutrinos found in these experiments were one of the other two types of neutrinos, not the electron neutrino that we expect coming from nuclear fusion in the Sun d. Now that they are working right, the chlorine experiments have found all the neutrinos that our models of the Sun have predicted should be coming e. The chlorine experiments found only between 1/3 the number of electron neutrinos arriving from the Sun that our models predicted should be coming

e. The chlorine experiments found only between 1/3 the number of electron neutrinos arriving from the Sun that our models predicted should be coming

21. Which of the following is NOT a product of the first step in the p-p chain of nuclear fusion? a. a form of hydrogen b. a positron c. a neutrino d. a deuteron e. a form of helium

e. a form of helium

0. In the Sun, when a positron and an electron collide, they will produce: a. a deuteron b. a neutron c. hydrogen d. a neutron e. energy in the form of a gamma ray

e. energy in the form of a gamma ray

3. In an earlier era, some scientists suggested that the energy of the Sun comes from meteorites (or, more properly, meteoroids) falling into it and converting their falling motion into heat. Which of the following is part of the argument that shows this mechanism will not work? a. the antimatter in the Sun would make the meteorites explode before they could do this b. a mass of meteorites equal to the mass of the Earth would have to fall in every century c. the meteorites would eventually increase the mass of the Sun and change the orbits of the planets d. since the Sun is made of gas, it does not have enough gravity to pull in meteorites e. more than one of the above

e. more than one of the above

16. When a large nucleus breaks apart (or is broken apart) into two smaller pieces, this is called a. nuclear fusion b. nuclear binding c. the p-p chain d. equilibrium breaking e. nuclear fission

e. nuclear fission

7. In the formula E=mc2, the letter c stands for a. the speed of sound b. the speed of an electron around the nucleus c. the amount of energy contained in one hydrogen nucleus d. the energy of a neutrino emerging from the Sun e. the speed of light

e. the speed of light