Physics Chapter 33

*both*

Which body is heated in its interior by nuclear processes? the sun the Earth both neither

*7.5 counts/min* After the first day: 1/2 =60c/m After second day: 1/4= 30c/m After third day: 1/8= 15c/m After fourth day: 1/16= 7.5c/m

A certain radioactive isotope placed near a Geiger counter registers 120 counts per minute. If the half-life of the isotope is one day, what will the count rate be at the end of four days? 5 counts/min 30 counts/min 7.5 counts/min 15 counts/min 10 counts/min

*Geiger counter*

A device used to measure radioactive decay.

*warmer than the environment.*

A sample of relatively active radioactive material is somewhat warmer than the environment. cooler than the environment. neither really

rem

Acronym of roentgen equivalent man; it is a unit used to measure the effect of ionizing radiation on human beings.

*lead.*

All deposits of natural uranium contain appreciable amounts of gold. lead. iron. all of these none of these particularly

*transmutation *

Conversion of an atomic nucleus of one element into an atomic nucleus of another element through a loss or gain in the number of protons.

*both of these* deuterium A stable isotope of hydrogen with a mass approximately twice that of the usual isotope. tritium A radioactive isotope of hydrogen with a mass approximately three times that of the common protium isotope.

Deuterium and tritium are both forms of hydrogen. isotopes of the same element. both of these neither of these

X-ray

Electromagnetic radiation, higher in frequency than ultraviolet, emitted by atoms when the innermost orbital electrons undergo excitation.

beta particle

Electron (or positron) emitted during the radioactive decay of certain nuclei.

*neutrino*

Elementary particle in the class of elementary particles called leptons. It is uncharged and almost massless; three kinds-electron, moun, and tau neutrinos, are the most common high-speed particles in the universe; more than a billion pass unhindered through each person every second.

*strong force *

Force that attracts nucleons to each other within the nucleus; a force that is very strong at close distances but decreases rapidly as the distance increases. Also called strong interaction.

*gamma ray*

High-frequency electromagnetic radiation emitted by atomic nuclei.

*beta particle* The beta particle because it is smaller so it is more penetrating. An electron has much less mass than a helium nucleus. - Given the same energy, the particle with less mass will travel faster and thus penetrate further

If an alpha particle and a beta particle have the same energy, which particle will penetrate farther into an object? beta particle alpha particle They both penetrate the same distance

*all of these* one alpha particle and 3 beta particles: loses 2 protons and 2 electrons , gains three protons= *1 proton gained* one positron and 2 beta particles: Loses one proton, and gains 2 protons= *1 proton gained* one beta particle: gains one proton= *1 proton gained*

In order for an atom to decay to an element which is one greater in atomic number, it can emit one alpha particle and 3 beta particles. one positron and 2 beta particles. one beta particle. all of these none of these

alpha particle

Nucleus of a helium atom, which consists of two neutrons and two protons, ejected by certain radioactive nuclei.

*electrostatically repelled.* It is repelled because it has a positive charge, by beta particles, which have a negative charge.

Once an alpha particle is outside the nucleus it is free to wander about the nucleus. radioactive. electrostatically repelled. quickly bound to a neighboring nucleus.

quark

One of the two classes of elementary particles (the other is the lepton). Two of the six quarks (up and down) and the fundamental building blocks of nucleons (protons and neutrons.)

*nucleon*

Principal building block of the nucleus; a neutron or a proton; the collective name for either or both.

*ionization *

Process of adding or removing electrons to or from the atomic nucleus.

carbon dating

Process of determining the time that has elapsed since death by measuring the radioactivity of the remaining carbon-14 isotopes.

*radioactivity*

Process of the atomic nucleus that results in the emission of energetic particles.

*beta ray *

Stream of beta particles (electrons or positrons) emitted by certain radioactive nuclei.

radioactive

Term applied to an atom having an unstable nucleus that can spontaneously emit a particle and become the nucleus of another element.

*more than half.* 75% of the radiation we encounter: natural background (cosmic rays, minerals, air) 15%: medical procedures 8% food ans water 2% consumer products <1% coal and nuclear plants

The amount of radiation we personally encounter that originates in the Earth's and the atmosphere's natural background is a trace amount. about a quarter. more than half. about half.

*protons.* They are both made of a high frequency electromagnetic wave not particles.

The atomic number of an element is the same as the number of its protons. nucleons. neutrons. neither of these

*one-quarter.* After one day= 1/2 After 2 days= 1/4

The half-life of an isotope is one day. At the end of two days the amount that remains is one-quarter. one-eighth. one-half. none. none of these

*cosmos.*

The origin of cosmic rays is the sun. cosmos. clouds. Earth. none of these

*radioactive decay in the Earth's core.*

The source of the Earth's natural heat is solar energy in the form of fossil fuels. molten-hot lava. radioactive decay in the Earth's core. pressure on the Earth's interior.

*electron clouds and the atomic nucleus.* X-rays are originate from the electron cloud of atoms gamma rays originate from the nucleus

The sources of X-rays and gamma rays, respectively, are both the atomic nucleus. the atomic nucleus and electron clouds. both electron clouds. electron clouds and the atomic nucleus. none of these

*half-life*

Time required for half the atoms of a radioactive isotope of an element to decay. This term is also used to describe decay processes in general.

*rad *

Unit used to measure a dose of radiation; the amount of energy (in centijoules) absorbed from ionizing ration per kilogram of exposed material.

*radiotherapy*

Use of radiation as a treatment to kill cancer cells.

*energy*' It does not lose any charge because Gamma radiation is made of a high frequency electromagnetic wave not particles. Charge is made of electrons which are a practical.

When a gamma ray is emitted by a nucleus, the nucleus then has less energy. charge. both of these neither of these

*changes, but its mass number remains constant.* * beta decay (β-decay) is a type of radioactive decay in which a neutron is transformed into a proton an atomic nucleus.* So when the beta particle is emitted, a proton and neutron switch places but the mass of the atom stays the same.

When a nucleus emits a beta particle, its atomic number changes, but its mass number remains constant. remains constant, but its mass number changes. remains constant, and so does its mass number. changes, and so does its mass number. none of these

*increases by 1.* * beta decay (β-decay) is a type of radioactive decay in which a neutron is transformed into a proton an atomic nucleus.* So when the beta particle is emitted, the mass of the atom stays the same. But ht atomic because the amount of protons increase.

When a nucleus emits a beta particle, its atomic number decreases by 2. decreases by 1. increases by 2. increases by 1. none of these

*decreases by 1.* When a positron is released it does the opposite of beta decay. Instead of changing a neutron to a proton. *It changes a proton to a neutron*

When a nucleus emits a positron, its atomic number doesn't change. increases by 1. decreases by 1.

Carbon-12 is more prominent in the food we eat. Carbon-12 is the most common isotope of carbon. Carbon-14 makes up less than one millionth of 1% of the carbon in the atmosphere. Although carbon-14 is radioactive, enough is not ingested to effect a person.

Which are more prominent in the food we eat, carbon-12 or carbon-14?

Larger nuclei tend to have more neutrons than protons. This is because protons and neutrons are held together by a strong force. However unlike neutrons, protons can also be repealed by an electric force. The farther protons are from each other in the nucleus, the higher the repelling electric force is between them. The closer they are the stronger, the strong force is. By adding neutrons to a nucleus, which does not have a repelling electric force, it straightens the nucleus, acting like a cement and holding together protons. In larger nuclei, where the proton on one side is farther from the proton on another, the electric force is increased. These larger nuclei require a ratio of more neutrons to protons to keep it stable.

Which contains the bigger percentage of neutrons, large nuclei or small nuclei?

*Carbon-14* carbon-12 is a common isotope of carbon and is not radioactive

Which of the following isotopes is radioactive? Carbon-12 Carbon-14 Both are radioactive. Neither is radioactive in nature.

*gamma radiation* Gamma radiation is made of a high frequency electromagnetic wave. electromagnetic radiation: is a wave that is composed of electric and magnetic fields.

Which of these is electromagnetic radiation? beta radiation gamma radiation debris of nuclear decay alpha radiation

Alpha and beta rays deflect in opposite directions because alpha waves have a positive charge, and are made from positive protons and neutrons that are neutral. They repel, and are repelled by the negatively charged beta particles that are made of electrons. Gamma rays are not deflected because they are not made of particles and have no charge, they are a high frequency wave.

Why are alpha and beta rays deflected in opposite directions in a magnetic field? Why are gamma rays not deflected?

*gamma rays.*

X-rays are similar to alpha rays. gamma rays. beta rays. all of these none of these

*alpha ray *

alpha ray Stream of alpha particles (helium nuclei) ejected by certain radioactive nuclei.