Chapter 16 Mass and Energy and the Theory of Relativity

At the end of the p-p chain of nuclear fusion in the Sun, hydrogen nuclei have been converted into:

a helium nucleus

According to the formula E=mc2,

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

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

Which of the following particles has the lowest mass?

a neutrino

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 Correct Response e. a form of helium

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

Which of the following is NOT one of the fundamental particles that we find inside atoms?

a. protons b. neutrons Correct Response c. positrons d. electrons e. all four of the above are found in most atoms

In the Sun, when a positron and an electron collide, they will produce:

energy in the form of a gamma ray

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?

for hydrogen nuclei to fuse, they must get very close to each other, which the nuclei in the oceans cannot do

What happens to the positron created during the p-p chain of nuclear reactions inside the Sun?

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

When a large nucleus breaks apart (or is broken apart) into two smaller pieces, this is called

nuclear fission

Today we realize that the source of energy for the Sun is a process called

nuclear fusion

Where in the Sun does fusion of hydrogen occur?

only in the core

The antimatter version of an electron is called a

positron

When two light elements collide to undergo nuclear fusion,

some of the energy in their mass is released

The strongest force we know is

the nuclear force which holds nuclei together

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?

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

In the formula E=mc2, the letter c stands for

the speed of light

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?

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

The process of fusion that keeps our Sun shining begins with which building blocks?

two protons