Combined Physics Exam 4 Questions
A stable electron orbit cannot exist if its circumference is
2.5 wavelengths.
*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.
In the electron-wave model of the atom, the orbit of an electron in the ground state contains
a single wavelength.
The spectral lines of atomic spectra are
as an identity of atoms as fingerprints are of people. orderly, and even predictable. images of the slit in a spectroscope.
Interference colors in a soap bubble is evidence that the soap film
both of these (has two reflecting surfaces, is thin)
A beam of electrons can be deflected by a
electric field. magnetic field.
The Ritz combination principle states that the sum of the
energy transitions of quantum jumps is consistent with the conservation of energy. frequencies of two lines in a spectrum often equal the frequency of a third line. energies associated with two lines in a spectrum often equal the energy associated with a third line
Light from two closely-spaced stars cannot produce a steady interference pattern due to
incoherence
in the double-slit experiment, fringes are more widely spaced when illumination is with monochromatic
low-frequency light
According to the well-known equation E=mc^2,
mass and energy are related
An excited atom decays to its ground state and emits a photon of red light. If instead the decay is to an intermediate state, then the light emitted could be
none of these
Physicists today consider the Bohr model of the atom to be
oversimplified, but nevertheless useful.
A beam of electrons has
particle properties and wave properties.
According to the correspondence principle, a new theory must
predict the same correct results as the old theory. overlap and agrees where the old theory works. account for confirmed results from the old theory.
Using the Schrödinger equation, scientists can calculate
probabilities
What did Millikan measure in his oil-drop experiment?
the electric charge of an electron
When an electron de-excites from the third quantum level to the second, and then to the ground state, two photons are emitted. The sum of the emitted frequencies equals the frequency of the single photon that would be emitted if de-excitation were from the third to
the ground state
When an electron de-excites from the third quantum level to the second, and then to the ground state, two photons are emitted. The sum of the emitted frequencies equals the frequency of the single photon that would be emitted if de-excitation were from the third to
the ground state.
Two spectral lines in a spectrum have frequencies of 2.0 x 10^14 Hz and 4.6 x 10^14 Hz. A higher-frequency line in the same spectrum likely has a frequency of
6.6 x 10^14 Hz.
A certain radioactive isotope placed near a Geiger counter registers 120 counts per minute (cpm). If the half-life of the isotope is one day, what will be the count rate at the end of the four days
7.5 cpm
*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
The first to be credited for assigning the terms positive and negative to electricity was
Benjamin Franklin.
*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.
Which radiation has no association with electric charge
Gamma
*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
The first to be credited with the idea that energy was quantized was
Max Planck.
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
*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?
*both*
Which body is heated in its interior by nuclear processes? the sun the Earth both neither
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
When waves from a pair of closely-spaced slits arrive in phase
a bright fringe is produced
A beam of electrons is employed in
a cathode-ray tube.
A spaceship whizzes past a planet at high speed. An observer on the planet sees a contracted spaceship, while an observer on the spaceship sees
a contracted planet
The correspondence principle applies to
all good theories.
Heisenberg's uncertainty principle
all of these
The superposition of waves can produce
all of these
The wave-particle duality applies to
all of these (photons, electrons, protons)
The more we know about a particle's position, the less we know about its
all of these (speed, momentum, kinetic energy)
*alpha ray *
alpha ray Stream of alpha particles (helium nuclei) ejected by certain radioactive nuclei.
The superposition of identical waves affects
amplitude
Some alpha particles pass through gold foil with very little deflection mainly because the
atoms of gold are mostly empty space.
According to Louis de Broglie, a material particle has
both of these (particle properties, wave properties)
According to Einstein's theory of special relativity
both of these (space and time are aspects of each other, energy and mass are aspects of each other)
When Rutherford directed a stream of alpha particles at a gold foil, some particles
bounced back continued through the foil deflected at a variety of angles
Objects moving at relativistic speeds appear to observers at rest to be
contracted
The discrete radii and energy states of atoms were first explained by electrons circling the atom in an integral number of
de Broglie wavelengths
You and a friend can share the same space and time measurements when
either of these
Comparing the light from a glowing tube of neon gas and the beam of helium-neon laser, there is a greater number of spectral lines in light from the
neon gas tube
For an isotope with a half-life of two days, at the end of four days the amount that remains is
one-quarter
Millikan was able to stop falling oil droplets in their paths by
opposing electric and gravitational forces.
Alpha and beta particles are deflected by a magnetic field in
opposite directions
Electric forces within an atomic nucleus tend to
push it apart
A lump of energy associated with light is called a
quantum and photon
According to de Broglie, constructive interference occurs when an orbiting wave
reinforces itself
According to the special theory of relativity, while traveling at very high speed your pulse rate
remains unchanged
After passing through double slits, electrons make a pattern on a screen that
resembles a pattern that waves make
Compared with the wavelengths of visible light, the wavelengths of matter waves in atoms are relatively
short
By scattering alpha particles from gold, Rutherford showed the atomic nucleus to be very
small relative to the atom and massive relative to the mass of an electron.
To outside observers at rest, the overall sizes of objects traveling at relativistic speeds are
smaller
Which is the strongest fundamental force
strong nuclear
The Schrödinger equation is most useful for describing
submicroscopic particles.
When an electron drops from a higher energy level to a lower one, energy is emitted. In comparison, how much energy is required to reverse the process, going from the lower level to the higher level?
the same energy
The discreteness of orbits of electrons in an atom are due to
wave interference.
Quantization of electron energy states in an atom is better understood in terms of the electron's
wave nature
Quantization of electron energy states in an atom is better understood in terms of the electron's
wave nature.
