Question 1

Particles emitted in radioactive decay have different penetrating power. The penetration depths of two particles, labeled X and Y, in a column of water are shown below. The X particle most likely is ________

Accepted Answer

The answer of Particles emitted in radioactive decay have different...

Question 2

Tissue damage caused by radiation is measured in units of sieverts (Sv) or rems. On average, a person living in the United States is exposed to 3.6 mSv of radiation each year. Space shuttle astronauts are exposed to about 25 rems of cosmic radiation during a mission. Roughly how does this quantity compare with the annual dose the astronaut would have received on the ground in the United States? (1 Sv = 100 rems)

Accepted Answer

25 rems is equivalent to 0.25 Sv or 250 mSv. The average annual exposure on the ground is 3.6 mSv, so 250 mSv is a bit less than 100 times more than 3.6 mSv.

Question 3

Exposure to ionizing radiation usually is measured in units of milliSieverts (mSv). For example, one mammogram produces an exposure of 0.4 mSv. A sievert accounts for ________

Accepted Answer

A sievert (Sv) is a unit that measures the health effect of low levels of ionizing radiation on the human body. It is a measure of the damage caused by the energy absorbed per kilogram of tissue, taking into account the biological effectiveness of the radiation (RBE). This makes it different from other units that measure radiation exposure, such as the gray (Gy), which only measures the amount of energy absorbed per kilogram of tissue without considering the type or effectiveness of the radiation.

Question 4

A number of techniques are used for diagnostic imaging of internal body organs. Which of these involve ionizing radiation and therefore pose a risk for cancer?
I. CT scan (X-ray computed tomography)
II. MRI scan (radio-wave magnetic resonance imaging)
III. US scan (ultrasound)
IV. Nuclear heart scan (radioactive tracer)
V. EKG (electrocardiograph)

Accepted Answer

CT scan and nuclear heart scan both involve ionizing radiation and can pose a risk for cancer. MRI, US, and EKG do not involve ionizing radiation and are considered safer imaging techniques.

Question 5

A number of techniques are used for diagnostic imaging of internal body organs. Which of these do not involve ionizing radiation and therefore do not pose a risk for producing cancer?
I. CT scan (X-ray computed tomography)
II. MRI scan (radio-wave magnetic resonance imaging)
III. US scan (ultrasound)
IV. Nuclear heart scan (radioactive tracer)
V. EKG (electrocardiograph)

Accepted Answer

MRI scans use radio waves and magnetic fields, ultrasound uses sound waves, and EKGs measure electrical activity of the heart. None of these involve ionizing radiation, unlike CT scans and nuclear heart scans which do use ionizing radiation.

Question 6

In assessing the severity of a radiological hazard, it is expedient to compare the level of exposure to the background radiation from the environment. A whole-body X-ray computed tomography scan (CT scan) produces an exposure of about 10 mSv (milliSieverts) compared to an annual background radiation exposure of approximately ________

Accepted Answer

The annual background radiation exposure for a typical person is approximately 3 mSv. This includes radiation from natural sources such as radon gas, cosmic radiation from space, and terrestrial sources.

Question 7

Electricity is produced from nuclear reactions by ________

Accepted Answer

Electricity is produced from nuclear reactions by using the energy to make steam to turn turbines. This is the common method used in nuclear power plants to generate electricity.

Question 8

Crews of commercial airlines are exposed to a higher level of background cosmic radiation during flight time than they would receive on the ground. A single round-trip, coast-to-coast flight gives a dose of about 0.012 rems. If a stewardess made 200 such flights in one year, how would her annual dose compare with a normal annual exposure on the ground of 3.6 mSv? (100 rem = 1 Sv)

Accepted Answer

The annual dose from 200 flights is 200 x 0.012 rems = 2.4 rems = 24 mSv. The normal annual exposure on the ground is 3.6 mSv, so 24 mSv is a bit less than 10 times more than 3.6 mSv.

Question 9

The purpose of control rods in a fission reactor is to ________

Accepted Answer

Control rods are made of materials that absorb neutrons, such as boron or cadmium. By inserting or withdrawing control rods, the rate of fission can be controlled, as the rods absorb some of the neutrons that would otherwise be available to cause additional fissions. This helps prevent the reactor from overheating or going critical.

Question 10

Which one of the following statements, A-D, is not correct? If all are correct, respond E.
A breeder reactor ________

Accepted Answer

Breeder reactors primarily use uranium-238, not uranium-235, to produce plutonium-239.

Question 11

Why is a nuclear power plant not in danger of producing a nuclear explosion?

Accepted Answer

The answer of Why is a nuclear power plant not...

Question 12

Which one of the following statements, A-D, is not correct? If all are correct, respond E.
A breeder reactor ________

Accepted Answer

The answer of Which one of the following statements, A-D,...

Question 13

The natural abundance of uranium-235 is ________

Accepted Answer

The natural abundance of uranium-235 is only a little less than 1%.

Question 14

Radioactive iodine-125 and palladium-103 decay by X-ray emission and are used in brachytherapy to treat cancer. Consider two patients, one being treated with I-125 and the other with Pd-103. Both receive a total dose of 145 Gy delivered over 10 months. What can be concluded from the data in the table about these treatments? Note: 1 keV = 1.602 * 10^-¹⁶ J. $$\begin{array} { | c | c | c | c | c | } \hline \text { Isotope } & \begin{array} { c } \text { X-ray Energy } \ \text { keV } \end{array} & \begin{array} { c } \mathbf { t } _ { 1 / 2 } \ \text { days } \end{array} & \begin{array} { c } \text { Initial Dose } \ \text { mGy/h } \end{array} & \begin{array} { c } \text { Initial Activity } \ \mathbf { m C i } \end{array} \ \hline \mathrm { L } - 125 & 27 & 60 & 80 & 0.42 \ \hline \mathrm { Pd } - 103 & 21 & 17 & 200 & 1.30 \ \hline \end{array}$$ I. The level of radiation is more uniform over the 10 months using I-125. II. Initially the level of radiation is higher using Pd-103. III. The density of sites damaged by radiation is higher initially using Pd-103.

Accepted Answer

The half-life of I-125 is longer than that of Pd-103, so the level of radiation will be more uniform over the 10 months using I-125. The initial dose rate is higher using Pd-103, so the level of radiation will be higher initially using Pd-103. The density of sites damaged by radiation is proportional to the dose rate, so the density of sites damaged by radiation will be higher initially using Pd-103.

Question 15

Cardiac pacemakers once used plutonium-238 as a power source. Plutonium-238 decays by the emission of gamma rays and alpha particles. This emission is not particularly harmful because ________

Accepted Answer

Gamma rays have high energy and can penetrate through materials, but are absorbed weakly by biological tissue. Alpha particles, on the other hand, have low energy and are stopped easily by materials, but can cause damage if they are taken into the body. In the case of cardiac pacemakers, the container prevents alpha particles from reaching biological tissue, and gamma rays are absorbed weakly by biological tissue. Therefore, the emission of gamma rays and alpha particles from plutonium-238 is not particularly harmful.

Question 16

Low-level nuclear waste from medical facilities generally requires only short-term storage before disposal because ________

Accepted Answer

Short-term storage is required for low-level nuclear waste from medical facilities because the radioactive isotopes used in medicine have short half-lives. This means that they rapidly decay and lose their radioactivity, making them safe for disposal within a short period of time.

Question 17

Uranium-235 is the fuel in nuclear power plants. When a nucleus of uranium-235 captures a neutron, the nucleus splits into two lighter nuclei and initiates a chain reaction. The chain reaction is driven by the emission of ________

Accepted Answer

The emission of neutrons from the splitting of uranium-235 nuclei initiates the chain reaction.

Question 18

The difference between the uranium used in an atomic bomb and that used in a nuclear power plant is that ________

Accepted Answer

The uranium-235 isotope is the one used for nuclear reactions in a bomb or in a nuclear power plant. However, the percentage of uranium-235 in the uranium used in a bomb is much higher compared to that used in a nuclear power plant. In a bomb, the uranium-235 is enriched to around 90%, while in a nuclear power plant, the uranium-235 is enriched to only around 3-5%.

Question 19

Radon gas is dangerous ________
I. because it binds to hemoglobin and inhibits the uptake of oxygen.
II. only if it is absorbed inside the body.
III. because it is an alpha emitter.

Accepted Answer

Radon gas is dangerous primarily because it is an alpha emitter (III), which can cause damage to lung tissue when inhaled. It is only dangerous if it is absorbed inside the body (II), as external exposure to alpha particles is generally not harmful.

Question 20

Among other problems with smoking, there is a danger from radiation, according to the following report! "Tobacco plants are grown in soils with high phosphate fertilizers that are naturally contaminated with the alpha-particle emitting radionuclide polonium-210. In one year, the average smoker will irradiate the bronchial epithelium with 8 to 9 rem, the equivalent dose of radiation from 250 to 300 chest X-ray films per year" (Pediatrics, September 1993, p. 464). How does this annual dose from tobacco compare to an average annual dose of 3.6 mSv that a nonsmoker receives from background radiation? (1 Sv = 100 rem)

Accepted Answer

The answer of Among other problems with smoking, there is...

Quiz 21: Nuclear Chemistry: Applications to Energy and Medicine

Exposure to ionizing radiation usually is measured in units of milliSieverts (mSv) . For example, one mammogram produces an exposure of 0.4 mSv. A sievert accounts for ________