Radiation Safety

Which of the following is essentially the sum total of air kerma over the exposed area of the patient's body surface? A. effective dose B. equivalent dose C. absorbed dose D. dose area product

D. dose area product

The first decay product of radium is A. radon B. cesium C. x-ray D. strontium

A. radon

Depending on the area of the body being examined with a fluoroscopic image intensification system, a range of __________ kVp is generally used for adult patients. A. 60 to 75 B. 75 to 110 C. 30 to 60 D. 110 to 140

B. 75 to 110

The whole-body TEDE regulatory limit for exposed personnel is __________ and __________ for the general public. A. 0.05 Sv; 0.001 Sv B. 0.15 Sv; 0.015 Sv C. 0.5 Sv; 0.1 Sv D. 0.25 Sv; 0.025 Sv

A. 0.05 Sv; 0.001 Sv

If the peak energy of the x-ray beam is 100 kVp, a protective lead apron must be the equivalent to at least which of the following measures? A. 0.25-mm thickness of lead B. 0.5-mm thickness of lead C. 1.0-mm thickness of lead D. 1.5-mm thickness of lead

A. 0.25-mm thickness of lead

Digital radiography systems offer several advantages over computed radiography. Some of these include 1. lower dose 2. ease of use 3. immediate imaging results 4. manipulation of the image A. 1, 2, 3, and 4 B. 1, 2, and 3 only C. 2, 3, and 4 only D. 1, 2, and 4 only

A. 1, 2, 3, and 4

Which of the following are advantages of the personnel digital ionization dosimeter? 1. Instant access to reports. 2. No waiting time for mailing dosimeters. 3. Lightweight and durable. 4. Can be dropped or scratched with little chance of harm to the device. A. 1, 2, 3, and 4 B. 1, 2, and 4 only C. 1, 2, and 3 only D. 2, 3, and 4 only

A. 1, 2, 3, and 4

Through which of the following routes can radon enter houses? 1. Crawl spaces under living areas. 2. Floor drains and sump pumps. 3. Porous cement block foundations. A. 1, 2, and 3 B. 1 and 3 only C. 2 and 3 only D. 1 and 2 only

A. 1, 2, and 3

To ensure that the lifetime risk of occupationally exposed persons remains acceptable, an additional recommendation is that the lifetime effective dose in mSv should not exceed A. 10 times the occupationally exposed person's age in years. B. 20 times the occupationally exposed person's age in years. C. 5 times the occupationally exposed person's age in years. D. the occupationally exposed person's age in years.

A. 10 times the occupationally exposed person's age in years.

0.2 Gy equals A. 200 mGy B. 2000 mGy C. 20 mGy D. 2 mGy

A. 200 mGy

What do radiation weighting factors take into consideration? 1. The overall risk of exposure to humans from ionizing radiation. 2. Both the internal and external dose measurements. 3. The fact that some types of radiation are more efficient at causing biologic damage than other types of radiation for a given dose. A. 3 only B. 2 only C. 1, 2, and 3 D. 1 only

A. 3 only

During a fluoroscopic examination, a resettable cumulative timing device measures the x-ray beam-on time and sounds an audible alarm or in some cases temporarily interrupts the exposure after the fluoroscope has been activated for what length of time? A. 5 minutes B. 1 minute C. 3 minutes D. 10 minutes

A. 5 minutes

What is the total average annual radiation equivalent dose for estimated levels of radiation exposure for humans? A. 6.3 mSv B. 2.0 mSv C. 3.2 mSv D. 9.6 mSv

A. 6.3 mSv

Which of the following radiation quantities is intended to be the best overall measure of the biologic effects of ionizing radiation? A. Effective dose B. Exposure C. There is no radiation quantity that is intended to be the best overall measure of the biologic effects of ionizing radiation. D. Absorbed dose

A. Effective dose

If the intensity of the x-ray beam is inversely proportional to the square of the distance from the source, how does the intensity of the x-ray beam change when the distance from the source of radiation and a measurement point is tripled? A. It decreases by a factor of 9 at the new distance. B. It increases by a factor of 3 at the new distance. C. It decreases by a factor of 3 at the new distance. D. It increases by a factor of 9 at the new distance.

A. It decreases by a factor of 9 at the new distance.

Terrestrial radiation includes which of the following sources? A. Long-lived radioactive elements such as uranium-238, radium-226, and thrium-232 that are present in variable quantities in the crust of the earth. B. Airport surveillance systems and electron microscopes. C. The sun and beyond the solar system. D. Radioactive fallout from nuclear weapons tests in which detonation occurred above ground.

A. Long-lived radioactive elements such as uranium-238, radium-226, and thrium-232 that are present in variable quantities in the crust of the earth.

Which of the following devices contains an aluminum oxide detector? A. Optically stimulated luminescence dosimeter. B. Pocket ionization chamber C. Digital ionization dosimeter D. Thermoluminescent dosimeter

A. Optically stimulated luminescence dosimeter.

A protective curtain, or sliding panel, with a minimum of 0.25-mm lead equivalent, should normally be positioned between the fluoroscopist and the patient to intercept which of the following types of radiation? A. Scatter radiation above the tabletop. B. primary radiation C. Exit or image-formation radiation D. direct radiation

A. Scatter radiation above the tabletop.

What is the purpose of radiographic beam filtration? A. To reduce exposure to the patient's skin and superficial tissues by absorbing most of the lower-energy photons from the heterogeneous beam. B. To reduce exposure to the patient's skin and superficial tissues by absorbing most of the higher-energy photons from the heterogeneous beam. C. To reduce exposure to the patient's skin and superficial tissues by absorbing all of the higher-energy photons from the homogeneous beam. D. To reduce exposure to the patient's skin and superficial tissues by removing all the lower-energy photons from the homogeneous beam.

A. To reduce exposure to the patient's skin and superficial tissues by absorbing most of the lower-energy photons from the heterogeneous beam.

Who discovered x-rays on November 8, 1895? A. Wilhelm Conrad Roentgen B. Thomas A. Edison C. Clarence Madison Daily D. Louis Harold Gray

A. Wilhelm Conrad Roentgen

The total kinetic energy released in a unit mass (kilogram) of air and expressed in metric units of joules per kilogram is A. air kerma B. effective dose C. equivalent dose D. absorbed dose

A. air kerma

Beta particles are actually A. high-speed electrons B. protons C. gamma rays D. x-rays

A. high-speed electrons

To visualize smaller and lower contrast objects during interventional procedures, high level control fluoroscopy uses exposure rates that are __________ those normally used in routine fluoroscopy. A. higher than B. lower than C. None of the above, because smaller and lower contrast objects cannot be visualized by fluoroscopy during interventional procedures. D. the same as

A. higher than

Reducing the field size to the anatomic features of interest not only reduces patient exposure, but also A. increases recorded image quality by decreasing scatter. B. increases recorded image quality by increasing scatter. C. decreases recorded image quality by increasing scatter. D. decreases recorded image quality by decreasing scatter.

A. increases recorded image quality by decreasing scatter.

As a result of technologic advances since the 1970s and strict regulations imposed within the United States by the FDA regarding consumer products containing radioactive material, the radiation exposure of the general public from such produces may now be considered A. negligible. B. substantial. C. very slight. D. moderate.

A. negligible

When spread over the inhabitants of the United States, fallout from nuclear weapons tests and other environmental sources along with other manmade radiations contributes A. only a small portion of 0.1 mSv to the equivalent dose of each person. B. a dose of approximately 1.5 mSv to the equivalent dose of each person. C. a dose of approximately 6.3 mSv to the equivalent dose of each person. D. a dose of approximately 3.2 mSv to the equivalent dose of each person.

A. only a small portion of 0.1 mSv to the equivalent dose of each person.

Which of the following is considered by the EPA to be the second leading cause of lung cancer in the United States? A. radon exposure B. cosmic ray exposure C. a fluoroscopic examination of the upper gastrointestinal tract D. annual PA and lateral chest radiographic images

A. radon exposure

Cosmic radiation occurs in which two forms? A. solar and galactic. B. natural background and artificial. C. artificial and galactic. D. solar and manmade.

A. solar and galactic

What instrument can be calibrated to read air kerma? A. standard, or free-air, ionizing chamber B. voltmeter C. coulomb counter D. amp meter

A. standard, or free-air, ionizing chamber

The protective tube housing serves as a shield against __________ entering the x-ray tube, thereby preventing electric shock while also facilitating cooling of the x-ray tube. A. the high voltage B. the low voltage C. lose inherent filter particles D. collimator components

A. the high voltage

Electromagnetic radiation travels or propagates through space in the form of a wave but can interact with matter as a particle of energy called a photon. This dual nature is referred to as A. wave-particle duality B. wave attenuation capability C. wave-particle phenomena D. wave-particle interchange ability

A. wave-particle duality

Which of the following units of measure are not SI units? 1. Roentgens 3. Coulombs per kilogram, grays, sieverts 3. Rads and rems A. 3 only B. 1 and 3 only C. 1 only D. 2 only

B 1 and 3 only

Secondary radiation includes 1. leakage radiation. 2. primary radiation. 3. scatter radiation. A. 1, 2, and 3 B. 1 and 3 only C. 2 and 3 only D. 1 and 2 only

B. 1 and 3 only

The millisievert (mSv) is equal to A. 1/10 of a sievert B. 1/1000 of a sievert C. 1/100 of a sievert D. 1/10000 of a sievert

B. 1/1000 of a sievert

Which of the following formulas is used to calculate effective dose? 1. EfD = (DxWR)1 + (DxWR)2 + (DxWR)3 2. EfD = D x WR x WT 3. EfD = D + Wr x WT A. 1, 2, and 3 B. 2 only C. 1 only D. 3 only

B. 2 only

Total filtration of __________ for fixed x-ray units operating above 70 kVp is the regulatory standard. A. 1.5-mm aluminum equivalent B. 2.5-mm aluminum equivalent C. 1.0-mm aluminum equivalent D. 1.5-mm aluminum equivalent

B. 2.5-mm aluminum equivalent

The Environment Protection Agency (EPA) recommends that action be taken to reduce elevated levels of radon in homes to a concentration less than A. 135 pCi/L B. 4 pCi/L C. 200 pCi/L D. 47 pCi/L

B. 4 pCi/L

Which of the following must always be the first step in protection of the reproductive organs? A. Use of digital imaging equipment. B. Adequate and precise collimation of the radiographic beam to include only the anatomy of interest. C. Use of a mobile protective shielding device. D. Use of gonadal shielding.

B. Adequate and precise collimation of the radiographic beam to include only the anatomy of interest.

Which of the following is not an x-ray beam limitation device? A. Collimator B. Filter C. Cone D. Extension Cylinder

B. Filter

Which of the following is a form of radiation that is capable of creating electrically charged particles by removing orbital electrons from the atom of normal matter through which it passes? A. Nonionizing radiation B. Ionizing radiation C. Subatomic radiation D. Ultrasonic radiation

B. Ionizing radiation

Any image that must be performed more than once because of human or mechanical error during the production of the initial image is considered to be a repeat image. What effect does a repeat image have on the radiation dose received by the patient? A. The patient's superficial tissues only receive a radiation dose that is four times as great as that of the original radiation dose. B. The patient's skin and possibly the gonads, if they were in the included imaged area, receive a double radiation dose. C. The patient's critical organs receive a radiation dose that is 10 times greater than the initial radiation dose. D. The patient receives no additional radiation dose.

B. The patient's skin and possibly the gonads, if they were in the included imaged area, receive a double radiation dose.

Which of the following is not a requirement that radiation survey instruments must meet? A. They should be able to detect all common types of ionizing radiation. B. They must all be equally sensitive in the detection of ionizing radiation. C. They should be calibrated annually to ensure accurate operation. D. They should interact with ionizing radiation similarly to the way human tissue reacts.

B. They must all be equally sensitive in the detection of ionizing radiation.

Which of the following is the SI unit of electric current? A. Coulomb per kilogram B. ampere C. sievert B. erg

B. ampere

When a properly calibrated automatic exposure control (AEC) is not employed to obtain a uniform selection of technical x-ray exposure factors, well-managed imaging departments A. have the radiologist determine and set up all technical exposure factor charts. B. make use of standardized technique charts that have been established for each x-ray unit in that facility. C. use technique charts borrowed from another imaging facility. D. estimate technical exposure factors for all radiographic examinations.

B. make use of standardized technique charts that have been established for each x-ray unit in that facility.

Luminance is determined by measuring the concentration of light A. at only one particular point on the field of view. B. over a particular field of view. C. at only one particular point on the field of view and then squaring the number. D. over a particular field of view and then squaring the number.

B. over a particular field of view.

When an exposed computed radiography imaging plate is ready to be processed, an imaging reading unit is used to scan the photostimulable phosphor imaging plate with a helium-neon laser beam. This process results in the emission of violet light that is changed into an electronic signal by a device called a A. scintillator. B. photomultiplier tube. C. photodiode. D. charge-coupled device array.

B. photomultiplier tube.

_______________ is essentially the radiation output weighted time that the unit is actually delivering radiation during the week. A. control designation B. workload C. occupancy D. use factor

B. workload

A flight on a typical commercial airliner results in an equivalent dose rate of A. 0.02 to 0.04 mSv/hr B. 0.001 to 0.005 mSv/hr C. 0.005 to 0.01 mSv/hr D. 0.05 to 0.09 mSv/hr

C. 0.005 to 0.01 mSv/hr

Which of the following radiation quantities use the same unit of measure? 1. effective dose and equivalent dose 2. exposure and effective dose 3. absorbed dose and equivalent dose A. 2 only B. 3 only C. 1 only D. 1, 2, and 3

C. 1 only

Which of the following are areas of the body that should be shielded from the useful beam whenever possible? 1. lens of the eye 2. breasts 3. thyroid gland 4. reproductive organs 5. all muscle tissues A. 2, 3, 4, and 5 only B. 1, 2, 3, and 5 only C. 1, 2, 3, and 4 only D. 1, 2, 3, and 5 only

C. 1, 2, 3, and 4 only

Of the following, which are disadvantages of using pocket ionization chambers as personnel dosimeters? 1. They can discharge if they are subjected to mechanical shock. 2. Because these devices provide no permanent legal record of exposure, health care facilities that use this method to record personnel exposure must delegate someone to keep such a record. 3. If not read each day, the dosimeter may give an inaccurate reading because the electric charge tends to escape. A. 2 only B. 3 only C. 1, 2, and 3 D. 1 only

C. 1, 2, and 3

When generator settings are changed from one mA and time combination to another, the most that linearity can vary is A. 50% B. 20% C. 10% D. 0%

C. 10%

If 400 people receive an average effective dose of 0.25 Sv, what is the collective effective dose? A. 1600 person-Sv B. 800 person-Sv C. 100 person-Sv D. 200 person-Sv

C. 100 person-Sv

In standard image intensification fluoroscopy, an x-ray beam half-value-layer (HVL) of 3 to 4.5 mm aluminum is considered acceptable when kVp ranges from A. 60 to 70 B. 70 to 80 C. 80 to 100 D. 50 to 60

C. 80 to 100

What organization was founded in 2007 that continues their pursuit to raise awareness of the need for dose reduction protocols by promoting pediatric-specified scan protocols to be used for both radiology and nonradiology users of CT? A. U.S. Food and Drug Administration B. American Registry of Radiologic Technologists C. Alliance for Radiation Safety in Pediatric Imaging D. The Joint Commission

C. Alliance for Radiation Safety in Pediatric Imaging

Which of the following personnel dosimeters are ordinary fountain pen externally? A. Thermoluminescent dosimeter B. Optically stimulated luminescence dosimeter C. Pocket Ionization chamber D. Personnel digital ionization dosimeter

C. Pocket Ionization chamber

__________ are the sensing devices most often used to measure skin dose directly. A. Lead-impregnated filters B. Molybdenum and rhodium filters C. Thermoluminescent dosimeters D. A sequence of aluminum equivalent filters of varying thicknesses

C. Thermoluminescent dosimeters

Three different filters are incorporated into the detector packet of the optically simulated luminescence dosimeter. Of what are these filters made of? A. aluminum, tin, and lead B. zinc, copper, and lead C. aluminum, tin, and copper D. zinc, copper, and barium

C. aluminum, tin, and copper

Why should the selection of technical exposure factors for all medical imaging procedures always follow ALARA? A. because radiation-induced cancer does have a dose level at which individuals would have a chance of developing this disease. B. so that referring physicians ordering imaging procedures do not have to accept responsibility for patient radiation safety. C. because radiation-induced cancer does not appear to have a dose level below which individuals would have no chance of developing this disease. D. so that radiographers and radiologists do not have to accept responsibility for patient radiation safety.

C. because radiation-induced cancer does not appear to have a dose level below which individuals would have no chance of developing this disease.

If ionizing radiation from natural sources grows larger because of accidental or deliberate human actions such as mining radioactive elements, the sources are termed A. artificial sources B. manmade sources C. enhanced natural sources D. extraterrestrial sources

C. enhanced natural sources

Occupational exposure of the radiographer can be kept as low as reasonably achievable (ALARA) through individual monitoring and other protective measures and the use of protective devices. Therefore, because exposure from radiation-related jobs will not alter the ______________________, radiation workers may receive a larger equivalent dose than members of the general population. A. mean glandular dose B. tissue tolerance dose C. genetically significant dose D. bone marrow dose

C. genetically significant dose

In digital radiography the number of different shades of gray that can be stored in memory and displayed on a computer monitor is termed A. shadows. B. contrast matrix. C. grayscale. D. pixels.

C. grayscale.

During a radiographic examination, which of the following combinations of technical exposure factors reduce patient radiation dose while still producing a diagnostic image? A. lower kVp, lower mAs B. higher kVp, higher mAs C. higher kVp, lower mAs D. lower kVp, higher mAs

C. higher kVp, lower mAs

Cataract formation, fibrosis, reduced fertility and sterility are classified as A. early tissue reactions of ionizing radiation. B. stochastic effects of ionizing radiation. C. late tissue reactions of ionizing radiation. D. hereditary effects of ionizing radiation.

C. late tissue reactions of ionizing radiation.

The term as low as reasonable achievable (ALARA) is synonymous with the term A. equivalent dose (EqD) B. diagnostic efficacy C. optimization for radiation protection (ORP) D. background equivalent radiation time (BERT)

C. optimization for radiation protection (ORP)

While standing behind the control-booth barrier, a radiographer makes a radiographic exposure. The x-rays scattered from the patient's body should ____________________. A. scatter a minimum of 10 times before reaching any area behind the control-booth barrier. B. scatter only once before reaching any area behind the control-booth barrier. C. scatter a minimum of 2 times before reaching any area behind the control-booth barrier. D. not have enough energy remaining that will reach behind the control-booth barrier.

C. scatter a minimum of 2 times before reaching any area behind the control-booth barrier.

Which of the following types of ionizing radiation produce virtually the same biologic effect in body tissue for equal absorbed doses? A. x-rays, alpha particles, and fast neurons B. alpha particles, beta particles, and gamma rays C. x-rays, beta particles, and gamma rays D. x-rays, neurons, and gamma rays

C. x-rays, beta particles, and gamma rays

According to the U. S. Public Health Service, the genetically significant dose (GSD) for the population of the United States is approximately A. 0.40 mSv B. 1.00 mSv C. 0.80 mSv D. 0.20 mSv

D. 0.20 mSv

Which of the following sources of radiation is manmade? 1. atmospheric fallout from nuclear weapons testing 2. cosmic radiation from the sun and beyond the solar system 3. nuclear power plant accidents as a consequence of natural disasters A. 2 and 3 only B. 1 and 2 only C. 1, 2, and 3 D. 1 and 3 only

D. 1 and 3 only

The maximum weekly permitted equivalent dose for a controlled area must not exceed A. 100 mSv. B. 2 mSv. C. 20 mSv. D. 1 mSv.

D. 1 mSv.

The annual effective dose limit for individual members of the general population not occupationally exposed is ___________ for continuous or frequent exposures from artificial sources other than medical irradiation and natural background and ____________ for infrequent annual exposure. A. 5 mSv; 9 mSv B. 3 mSv; 7 mSv C. 50 mSv; 25 mSv D. 1 mSv; 5 mSv

D. 1 mSv; 5 mSv

Which of the following are forms of electromagnetic radiation? 1. microwaves 2. visible light 3. x-rays 4. gamma rays 5. ultraviolet radiation A. 3, 4, and 5 only B. 1, 2, and 3 only C. 2, 3, and 4 only D. 1, 2, 3, 4, and 5

D. 1, 2, 3, 4, and 5

Fluoroscopic devices are capable of subjecting the patient, the equipment operator, and other personnel near the fluoroscopic equipment to substantial doses of ionizing radiation. These devices include 1. C-arm fluoroscopes 2. fluoroscopes on stationary equipment with HLC mode used for interventional procedures 3. biplane interventional fluoroscopic systems A. 1 and 3 only B. 2 and 3 only C. 1 and 2 only D. 1, 2, and 3

D. 1, 2, and 3

The advantages of the BERT method are 1. it does not imply radiation risk; it is simply a means for comparison. 2. it emphasizes that radiation is an innate part of our environment. 3. it provides an answer that is easy for the patient to comprehend. A. 1 and 2 only B. 1 and 3 only C. 2 and 3 only D. 1, 2, and 3

D. 1, 2, and 3

The cardinal principles of radiation protection include which of the following? 1. Time 2. Distance 3. Shielding A. 1 only B. 2 only C. 3 only D. 1, 2, and 3

D. 1, 2, and 3

What is the latent period for most radiation-induced cancers? A. 1 year B. 5 years C. 7 years D. 15 years or more

D. 15 years or more

What is the maximum period of time that a thermoluminescent dosimeter(TLD) may be worn as a personnel device? A. 1 hour B. 1 week C. 1 month D. 3 months

D. 3 months

Who was the first American radiation worker to die from radiation-induced cancer in October of 1904? A. Wilhelm C. Roentgen B. Marie Curie C. Thomas A. Edison D. Clarence Madison Daily

D. Clarence Madison Daily

What unit is used to measure radiation exposure in the metric International System of Units? A. Milligray B. Sievert C. Millisievert D. Coulomb per kilogram

D. Coulomb per kilogram

When changing employment, what must a radiation worker convey to his/her new employer? A. A report of all procedures performed when 'on call' after regular hours. B. A list of all fluoroscopic procedures performed daily. C. A list of all radiographic procedures performed daily. D. Data pertinent to accumulated permanent equivalent dose to be placed on file.

D. Data pertinent to accumulated permanent equivalent dose to be placed on file.

Which of the following provides the basis for determining whether an imaging procedure or practice is justified? A. NEXT program B. ALARA concept C. BERT method D. Diagnostic efficacy

D. Diagnostic efficacy

What is the most common unit of measure of equivalent dose? A. Milligray B. Coulomb per kilogram C. Microsievert D. Millisievert

D. Millisievert

When the sensing crystals contained in the thermoluminescent dosimeter are irradiated, which of the following occurs? A. The electrons freed from the LiF molecule are trapped at a lower energy level of bands. B. The protons in the crystalline lattice structure of the LiF molecule absorb energy and are excited to a higher energy level of bands. C. The neutrons in the crystalline lattice structure of the LiF molecule absorb energy and are excited to a higher energy level of bonds. D. Some of the electrons in the crystalline lattice structure of the LiF molecule absorb energy and are excited to higher energy levels or bands.

D. Some of the electrons in the crystalline lattice structure of the LiF molecule absorb energy and are excited to higher energy levels or bands.

What do optically stimulated luminescence dosimeters (OSLs), thermoluminescent dosimeters, digital ionization dosimeters, and pocket ionization chambers have in common? A. These devices are all used for area monitoring. B. These devices all use the same sensing material to detect ionizing radiation. C. Each of these devices can only be used for personnel monitoring for a maximum of 6 months. D. These devices are all used for personnel monitoring.

D. These devices are all used for personnel monitoring.

Which of the following helps shield the global population from exposure to essentially all high-energy, bombarding cosmic rays? A. fog B. clouds C. smog D. atmosphere and magnetic field of the Earth

D. atmosphere and magnetic field of the Earth

When using digital fluoroscopy systems, making use of the last image hold feature can A. lead to a 50% reduction of technical exposure factors. B. eliminate the need to collimate the primary beam. C. eliminate the need for body or part immobilization. D. be an effective dose reduction technique.

D. be an effective dose reduction technique.

Because multiple bony areas span the entire body, the radiation dose absorbed by the organ called bone marrow A. is not of concern during any diagnostic radiography examinations. B. can only be measured to a small degree by a direct method. C. can be accurately measured by a direct method. D. cannot be measured by a direct method; it can only be estimated.

D. cannot be measured by a direct method; it can only be estimated.

According to the American College of Radiology (ACR), abdominal radiologic examinations that have been requested after full consideration of the clinical status of a patient, including the possibility of pregnancy, need A. to be postponed and scheduled at least 10 days after the start of the next menstrual period. B. to be postponed or selectively scheduled. C. to be postponed and scheduled 10 days before the end of the next menstrual period. D. not be postponed or selectively scheduled.

D. not be postponed or selectively scheduled.

In the electromagnetic spectrum, higher frequencies are associated with A. longer wavelengths and lower energies B. shorter wavelengths and lower energies C. longer wavelengths and higher energies D. shorter wavelengths and higher energies

D. shorter wavelengths and higher energies

When exposed to high radon levels in the home, which of the following groups of people have the highest risk of developing lung cancer? A. teenagers B. adults from 20 to 30 years of age C. nonsmokers D. smokers

D. smokers