RAD Midterm 1 TCDHA Exam 2026 | Radiography Study Guide & Practice Questions
define radiation vs radioactivity - (answer)o Radiation: Radiation is the emission and propagation of
energy through space or a substance in the form of waves or Particles
o Radioactivity: radioactivity is the process by which certain unstable atoms or elements undergo
spontaneous disintegration, or decay in an effort to attain a more balanced nuclear state
define sharpness of image - (answer)clarity of detail or structures on a film,
influenced by: traditional film composition, movement, focal spit size
define movement in regard to sharpness of a digital image - (answer)if PID, receptor or lint moves the
sharpness will be affected and will be blurred due to penumbra on both sides
PENUMBRA: the lighter, outer part of a shadow—or a region of partial illumination—that occurs when
an object only partially obscures a light source
define magnification - (answer)enlargement of an image caused by divergence of the beam and distance
factors
affected by target- receptor and object receptor
define target receptor: - (answer)distance from source of x-rays to the image receptor, determined by
the length of the PID. a longer PID ensures parallel x-rays hit the receptor causing less magnification
THEREFORE, more distance is better
define object receptor: - (answer)distance from object being radiographed to the image receptor. they
should be placed as close as possible to reduce magnification
THEREFORE less distance is better
define distortion: - (answer)variation in the true size of an object being radiographed. the image is not
the same size as the actual object
factors that influence are; object receptor alignment, x-ray beam angulation, elongation, foreshortening
,RAD Midterm 1 TCDHA Exam 2026 | Radiography Study Guide & Practice Questions
define object receptor alignment: - (answer)both must be parallel, if they aren't the image will be
distorted (to long or too short)
define x-ray beam angulation - (answer)x-ray beam must be perpendicular to the tooth and receptor
(central ray must be perpendicular as possible to tooth and receptor)
define elongation: - (answer)too long, angle is too flat
define foreshortening: - (answer)too short, angle is to steep
define matter - (answer)anything that occupies space and has mass, can be liquid, gas, solid
define energy - (answer)ability to do work and overcome resistance whenever matter is altered (kinetic-
movement and potential- wood, petroleum etc)
define an atom - (answer)fundamental unit of matter
central nucleus and orbiting electrons
identity is determined by the composition of the nucleus and the arrangement of orbiting electrons
define radiation - (answer)radiation is the emission and propagation of energy through space or a
substance in the form of waves or particles
define radioactivity - (answer)radioactivity is the process by which certain unstable atoms or elements
undergo spontaneous disintegration, or decay, in an effort to attain a more balanced nuclear state
what 2 groups is ionizing radiation classified as ? - (answer)particulate radiation
electromagnetic radiation
define electromagnetic radiation - (answer)this is the propagation of WAVELIKE ENERGY (without mass)
through space or matter
, RAD Midterm 1 TCDHA Exam 2026 | Radiography Study Guide & Practice Questions
all have common characteristics: may be classified as ionizing or non-ionizing
only high energy radiations are capable of ionization (x-rays, gamma rays, cosmic rays, light,
microwaves)
what 2 different concepts can electromagnetic radiation be broken down into? - (answer)the particle
theory
the wave theory
define the "wave particle theory" - (answer)electromagnetic radiation= moving as either particles or
waves through space and matter
when electrons return to a low energy -> release a pocket of energy (photon)-> photon resembles a
particle but moves like a wave and vice versa (can resemble a wave but behave like a particle)
define the particle concept - (answer)characterizes electromagnetic radiation in terms of discrete
bundles of energy called photons/quanta
- photons are bundles of energy with no mass or weight
photons travel as waves at the speed of light and move through space in a straight line
define the wave concept - (answer)characterizes electromagnetic radiation as waves
includes: velocity, frequency, wavelength
=energy and penetrating power, shorter the wavelength the greater the penetration, conversely the
longer the wave length the less penetrating
define X- radiation - (answer)x-radiation is high energy, ionizing electromagnetic radiation in the form of
waves
define velocity - (answer)speed of the wave
define frequency - (answer)long wave= low frequency
short wave= high frequency (more waves)
define radiation vs radioactivity - (answer)o Radiation: Radiation is the emission and propagation of
energy through space or a substance in the form of waves or Particles
o Radioactivity: radioactivity is the process by which certain unstable atoms or elements undergo
spontaneous disintegration, or decay in an effort to attain a more balanced nuclear state
define sharpness of image - (answer)clarity of detail or structures on a film,
influenced by: traditional film composition, movement, focal spit size
define movement in regard to sharpness of a digital image - (answer)if PID, receptor or lint moves the
sharpness will be affected and will be blurred due to penumbra on both sides
PENUMBRA: the lighter, outer part of a shadow—or a region of partial illumination—that occurs when
an object only partially obscures a light source
define magnification - (answer)enlargement of an image caused by divergence of the beam and distance
factors
affected by target- receptor and object receptor
define target receptor: - (answer)distance from source of x-rays to the image receptor, determined by
the length of the PID. a longer PID ensures parallel x-rays hit the receptor causing less magnification
THEREFORE, more distance is better
define object receptor: - (answer)distance from object being radiographed to the image receptor. they
should be placed as close as possible to reduce magnification
THEREFORE less distance is better
define distortion: - (answer)variation in the true size of an object being radiographed. the image is not
the same size as the actual object
factors that influence are; object receptor alignment, x-ray beam angulation, elongation, foreshortening
,RAD Midterm 1 TCDHA Exam 2026 | Radiography Study Guide & Practice Questions
define object receptor alignment: - (answer)both must be parallel, if they aren't the image will be
distorted (to long or too short)
define x-ray beam angulation - (answer)x-ray beam must be perpendicular to the tooth and receptor
(central ray must be perpendicular as possible to tooth and receptor)
define elongation: - (answer)too long, angle is too flat
define foreshortening: - (answer)too short, angle is to steep
define matter - (answer)anything that occupies space and has mass, can be liquid, gas, solid
define energy - (answer)ability to do work and overcome resistance whenever matter is altered (kinetic-
movement and potential- wood, petroleum etc)
define an atom - (answer)fundamental unit of matter
central nucleus and orbiting electrons
identity is determined by the composition of the nucleus and the arrangement of orbiting electrons
define radiation - (answer)radiation is the emission and propagation of energy through space or a
substance in the form of waves or particles
define radioactivity - (answer)radioactivity is the process by which certain unstable atoms or elements
undergo spontaneous disintegration, or decay, in an effort to attain a more balanced nuclear state
what 2 groups is ionizing radiation classified as ? - (answer)particulate radiation
electromagnetic radiation
define electromagnetic radiation - (answer)this is the propagation of WAVELIKE ENERGY (without mass)
through space or matter
, RAD Midterm 1 TCDHA Exam 2026 | Radiography Study Guide & Practice Questions
all have common characteristics: may be classified as ionizing or non-ionizing
only high energy radiations are capable of ionization (x-rays, gamma rays, cosmic rays, light,
microwaves)
what 2 different concepts can electromagnetic radiation be broken down into? - (answer)the particle
theory
the wave theory
define the "wave particle theory" - (answer)electromagnetic radiation= moving as either particles or
waves through space and matter
when electrons return to a low energy -> release a pocket of energy (photon)-> photon resembles a
particle but moves like a wave and vice versa (can resemble a wave but behave like a particle)
define the particle concept - (answer)characterizes electromagnetic radiation in terms of discrete
bundles of energy called photons/quanta
- photons are bundles of energy with no mass or weight
photons travel as waves at the speed of light and move through space in a straight line
define the wave concept - (answer)characterizes electromagnetic radiation as waves
includes: velocity, frequency, wavelength
=energy and penetrating power, shorter the wavelength the greater the penetration, conversely the
longer the wave length the less penetrating
define X- radiation - (answer)x-radiation is high energy, ionizing electromagnetic radiation in the form of
waves
define velocity - (answer)speed of the wave
define frequency - (answer)long wave= low frequency
short wave= high frequency (more waves)
