C. Conversion of dps to dpm means multiplying by 60 seconds. The converting mCi to Ci requires multiplying by 1000 or 103
The half-life of iridium 192 is 74 days. The decay constant is:
a. 3.7 days-1
b. 37 days-1 c. 106.6 days-1
d. 0.0094 days-1
e. 0.027 days-1
d. Given by the formula λ=ln2/T1/2
What are the differences between the electron and proton?
Electrons are light, negatively charged particles; they can collide and interact with other particles.
Protons are heavy, positively charged particles; only interact with electrons
Types of nuclear decay include all of the following except:
B. Types of nuclear decay include alpha, beta negative and positive, electron capture, internal conversion, fission and fusion aftermaths
During x-ray production, the resulting x-ray beam comes from electrons colliding with the target causing interactions such as:
D. During ionization characteristic x-rays may be produced. If the electron comes close to the nucleus, bremsstrahlung radiation may result. Auger electrons may be emitted as a result of another electron filling an empty space left by the ejected electron.
The positive side of the basic x-ray tube is known as the:
D. In the basic x-ray tube, the anode receives the streaming electrons and is known as the positive side of the tube.
A radioactive source has an initial activity of 60 mCi. Its half-life is 8 days. What is the remaining activity after 10 days?
B. Use the activity formula A= Ao e-λt
The average life of the source above is:
D. Use the formula Average life=1.44(T1/2)
The ratio of x-ray to heat during x-ray production is:
B. As the maximum energy increases, more of the converted energy becomes photons
The radioactive decay of a radioisotope is characterized by its:
D. The decay constant expresses how many atoms are lost over time
An elastic collision is one in which:
B. In elastic collisions the incoming electrons gives up all of its energy. On the other hand, inelastic collisions may allow bounce back where the incoming electron shares its energy
The energy of an electromagnetic radiation is inversely proportional to its:
A. The electromagnetic spectrum shows wavelengths shortening as energy increases
If a 50 keV electron collides with an inner shell electron with a binding energy of 25 keV, the resulting photoelectron will have an energy of:
B. The outgoing photoelectron has an energy that is the difference between the incoming electron and the binding energy of the electron collided
The energy of an electromagnetic radiation is directly proportional to its:
A. The electromagnetic spectrum show that the frequency increases as the energy of radiation increases
Photon Interactions include______.
Electron interactions include____.
Electron Interactions: Bremsstrahlung, Characteristic
The decay of cobalt-60 to table lead is an example of ___ decay.
A. As radioactive Cobalt transforms, gamma rays and beta negative particles are emitted
Regarding isotopes; isotopes of an element have the same number of ____ but a different numbers of neutrons.
Protons. Radionuclides with the same number of protons but different number of neutrons are known as isotopes
A photon of 25 Ä has a kinetic energy of ______ KeV.
0.496 KeV
E= 12.4/λ
E=12.4/25 A
E=0.496 KeV
If the decay constant of a particular isotope is 45 sec-1, the half-life is ____.
0.0154 sec
T1/2=.693/λ
T1/2=.693/ 45 sec-1
T1/2=.0154 sec
If the half-life of cobalt-60 is 5.26 years, the average life is _____
7.59 years
Ta=T1/2/.693
Ta=5.26/.693
Ta=7.59 years
If using a tungsten target, the fraction of 4 MeV electrons converted to photons is ____.
0.1036 or 10.36%
F=3.5x10-4 (74) (4 MeV)
F=0.1036
Which has the highest photon energy?
A. The electronmagnetic spectrum shows UV light with higher energy and frequency than the other photons mentioned
The probability of a photoelectric interaction (increases/decreases) with increasing energy and (increases/decreases) with the atomic number of the medium.
Decrease, Increase. The probability of photoelectric interactions decreases as energy increases. The probability of photoelectric interactions increases as the atomic number of the medium increases.
The majority of the mass of the atom is derived from:
C. Bohr's model shows the massive part of the atom being the nucleus where protons and neutrons reside
A neutral atom that loses an electron by ionization is called a:
B. Loss of an electron leaves an imbalance to the atom. Positive charge would then be greater than negative charges
After alpha decay, the daughter nuclide will have an atomic mass number ___ amu lower than the parent.
C. An alpha particle is composed of 2 neutrons and 2 protons. Loss of these particles would be a loss of 4 atomic mass units
A certain atom has binding energies of 70 eV in the L shell and 10 eV in the M shell. During an M shell to L shell transition, the photon emitted will have an energy of:
A. The emitted photon has an energy that is the difference between the binding energies of transitioning electrons
What type of nuclear decay is realized when:
a. 88Ra226 decays to 86Rn222 ____
b. 11Na22 decays to 10Ne22 ____
a. Alpha decay
b. Beta positive
An atom is neutral if the number of its electrons is equal to its:
A. Electrons have negative charge, protons positive charge. When equal, they neutralize the atom
What is the threshold energy for pair production:
C. During pair production, two particles of equal energies -.511 MeV are emitted. The incoming photon has to have at least that photon has to have at least that combined energy
Solve for λ in hours-1
A= 10 mCi
Ao= 18 mCi
t= 50 hours
A=Aoe-λt
5 mCi= 18 mCi e-λ(50)5/8=e-λ(50)
ln 5/18=ln(e-λ(50))
-1.28=-λ(50)
λ=.0256-1hours
Solve for Ao
A= 10 mCi
T1/2= 8 hours
t=22 hours
λ=.693/8hrs, λ=.087-1hours
10mCi=-Aoe-.087(22)
Ao=67.57 mCi
The System International unit for activity is the:
D. Activity is expressed in units of Curie or Becquerel. The Becquerel is the SI unit
To interact by photoelectric effect, the interacting photon must have energy:
D. Photoelectric effect occurs when a photon interacts with a tightly bound electron. Its energy has to be equal to or greater than the binding energy
The photons produced during the orbital transitions of electrons from a higher to lower energy are called:
B. Characteristic radiation is emitting when electrons switch places in the shells of the atom
An electron with the lowest binding energy is most likely located in the:
A. The farther away from the nucleus, the lower the binding energy
Two or more chemicals with the same chemical formula, but having different nuclear states are known as:
B. Isomers are the same element but in an excited state
Which is not true of the electromagnetic spectrum? They all have the same:
C. Electromagnetic radiations have the potential to travel at the same speed, they have virtually no mass and carry no charge
Radon has a half-life of 3.83 days. Its average life is:
C. Use the formula Average life = 1.44 (T1/2)
Carbon-14 and nitrogen-14 are:
A. Isobars have the same mass
How many disintegrations per minute (dpm) are there in 1 Ci?
A. 1 Ci=3.7 x 1010 dps. Covert to minutes by multiplying by 60
How many electrons are there in 1 g of tissue?
a. 3 x 1010 b. 3 x 1023 c. 6.02 x 1023
d. None of the above
d. The number of electrons per gram as been computed using Helium as a reference. For Helium 3x10^23 is the number of electrons per gram. Tissue in the question has not been specified as soft tissue or bone, both having a different atomic weight than helium
On January 1, we received 80 mCi of an isotope with a half-life of 8 days. The activity remaining on January 25 would be:
A. 24 days have elapsed. This would be 3 half-life periods for this isotope. 3 half lives would leave about 12.5% of the initial activity. 80 mCi (12.5%) = 10 mCi. The activity formula could also be used
The fraction of cobalt-60 atoms remaining after 10 years is approximately:
A. The half-life of Cobalt is 5.26 years. 10 years is approximately 2 half lives, leaving about 25% of the original atoms
The wavelengths of x-rays are measured in:
C. The Angstrom is the unit of measure for the wavelength
The relationship between mass and energy is given by Einstein's equation: E=mc2 The C stands for:
B. C in Einstein's equation is the speed or velocity of light. Option D has incorrect time units
The photoelectric process is essentially an interaction between a photon and:
C. Photoelectric effect often occurs with an electron tightly bound and in the inner shells of the atom
As the wavelength of light is decreased, its speed is:
B. All radiations in the electromagnetic spectrum have the same speed/velocity regardless of wavelength or frequency
The frequency of radiation with a wavelength of 5 x 10^-7 meters is:
B. use the formula C=λν
A radionuclide decays at the rate of 20% per hour. Its half-life is approximately:
D. use the formula T1/2=.693/λ
Bragg peak is:
A. Bragg peak shows maximum ionization at the end of the range for heavy, high LET particles
Different isotopes of the same element will have equal numbers of ______
A. Isotopes have the same number of protons and different neutrons. The number of protons and electrons are equal in a neutral atom
A radioactive source has a half-life of 6 hours and an activity of 10 mCi at noon on Monday. The activity at noon on Tuesday will be ____mCi.
A. The time elapsed has been 4 half-lives. The activity may be found by multiplying the initial activity by 0.5^4. Or the formula A=Aoe^(-λt) may also be used
The half-life of a radionuclide is:
D. The average life is given by the formula: Ta=1.44 (T1/2). So, the half-life is less than the average life. The average life comes close to what may be thought of as the life span for a radioactive nuclide
In the formula A=Aoe-λt, λ is ____.
D. The symbol in the activity formula is the decay constant and expressed the constant fraction of atoms decaying in a certain amount of time
When a very long-lived radionuclide decays to a short-lived daughter, it is known as ___equilibrium.
A. Secular equilibrium occurs when the parent nuclide has a longer half-life than a daughter product
Which of the following is not a type of ionizing radiation?
A. Ultrasound is not electromagnetic radiation
An electron, proton, and alpha particle each have 20 MeV kinetic energy. Which of the following is true?
B. The electron's mass is low compared to its kinetic energy so it must be traveling at about light speed. The alpha particle has the greatest total energy
The mass of an electron is:
C. protons, neutrons and nucleons have a mass about 1800 times that of an electron
Ionization implies:
A. When an atom is ionized, an electron is ejected from the atom
A deuteron is the nucleus of an isotope of H2. Which of the following is true?
B. The number in the upper right indicates the atomic mass
When a radionuclide decays, radiation is emitted from the:
C. Unstable radioactive nuclides has excess energy in its nucleus. The nucleus achieves stability by redistributing energy between the nucleons
The probability that a photon interacts with a material is:
B. The total attenuation coefficient represents the sum of all possible interactions
The rate of energy loss by a charged particle is:
B. Energy loss is proportional to the square of particle charge and inversely proportional to the square of its velocity
Heavy particles lose most of their energy
A. This maximum energy loss is known as Bragg peak
Bragg peak is not observed in electrons because of their:
B. Electrons have low mass and therefore deposit energy as it moves quickly through the medium
Excitation produced by electron beams occurs in the:
D. The energy transferred is not enough to eject the electron. The incoming electron does not have an energy higher than the binding energy of the orbiting electron
In the production of bremsstrahlung, the electron:
B. The strong electromagnetic field of the nucleus decelerates the electron as it approaches. In the deceleration, some of the energy is lost in the form of an x-ray photon called bremsstrahlung
The term xray refers to a part of the electromagnetic spectrum having an energy of:
A. The electromagnetic spectrum shows xrays having energy of at least 124 eV
Which of the following types of radiation has a positive electrical charge?
C. Alpha particles have a positive charge
Radiation can be described as energy:
C. Radiation is energy in motion
I131 and I125 have different:
E. The formulas show the element Iodine which has the same chemical properties. The mass number is different, and the z number is the same at 53 protons so the number of neutrons are different
If the distant from a radiation source is decreased by half, the intensity is:
B. Inverse square law says the intensity of radiation is inversely proportional to the distance by a square of distance change
106 photons from a source are incident on a 1.5 cm thick lead plate. The HVL of the beam in lead is 1.1 cm. The number of photons transmitted through the lead plate would be:
N=Noe^(-μt)
N=389,000
108 photons from a source are incident on a water tank 0.2 meters thick. The linear attenuation coefficient of this beam in water is 11.55 m-1. The number of photons transmitted through this 0.2 meters of water would be:
