Physics Springs 2025

velocity

The distance traveled, divided by time necessary to cover the distance (V=d/t). Unit of measure: m/s

acceleration

subtracting initial velocity of an object from its final velocity and dividing that value by time used (Vf-vo/t). Unit of measure: m/s

force

push, pull, or action that changes motion of an object (F=MA). Unit of measure: Newtons

momentum

equal to mass of an object multiplied by its velocity (P=MV). Unit of measure: kg-m/s

work

expression of force applied to object multiplied by distance across which it is applied (F x D). Unit of measure: Joule

power

work divided by time during which work is done (P= work/time). Unit of measure: Watts

velocity, acceleration, force, momentum, work, power

what are the radiologic quantities derived from the fundamental quantities of mass, length, time

British system (standard) and the system international (metric)

what are the 2 systems of measure commonly used in radiologic sciences

mass

the quantity of matter contained in an object

matter

anything that occupies space and has shape/form

pound

measure of gravitational force exerted on the body

meter

what is the SI unit for length

inertia

object with mass that resists change in state of motion

an object at rest will stay at rest unless acted on by an external force

state Newton’s law of motion

energy

the ability to do work

energy in a stored state

define potential energy

energy being expended

define kinetic energy

roentgens, rad, rem, curies

what are the standard units that quantify radiation doses

quantify radiation intensity

define roentgen

biologic radiation effects on humans/animals

define rad

quantify occupational exposure

define rem

measure of electrons liberated by ionization

define coulomb/kilogram

removal of electrons from atoms

define ionization

quantify of radiation energy absorbed by tissues irradiated

define gray

absorbed dose

what is the unit of gray is

quantify occupational exposure/dose equivalent

define sievert

biologic effects of different types of radiation in which a radiation worker may be exposed

know what sievert addresses

quantify radioactivity

define becquerel

standard unit for radioactivity

define curie

radioactive atom gives off particles and energy in an effort to regain a stable state

define disintegration (decay)

tube, collimator, table, control console, tube stand, and wall unit

what does permanently installed equipment consist of

special diode 2 electrodes tube that converts electrical energy into x-rays and heat

know what x-ray tube is and what it does

positive: anode, negative: cathode

know what positive and negative electrodes are

anode = over the head, cathode = on the floor

know which part of the tube is commonly situated over the head and which on the feet

metal with special mounting bracket for the x-ray tube and high voltage receptacles to deliver electricity to x-ray tube

know what the tube housing is

dissipate the heat produced

know the purpose of oil surrounding the tube housing

box shaped device attached to the bottom of the housing and restricts x-ray beam to an area of an interest

know what collimator is and what it does

reflects light source through plastic and casts a shadow of crosshairs

know the function of the mirror in the collimator

adjust the size of the light field

know the function of the shutters within the collimator

portion of the tube head that allows for mobility

know the function of the tube stand

as low as reasonably achievable

Define ALARA

radiographer is responsible for minimizing radiation dose to patient, self, and other healthcare members

know what the code of ethics specifically states in regards to radiation protection

time, distance, shielding

know the 3 cardinal rules

use of radiopaque materials to reduce radiation exposure to areas of patient/employees not necessary be exposed

define shielding

1/16” of lead placed in the wall and floor where the primary beam is directed

be able to define and know the specifics of a primary beam

1/32” of lead placed in the wall and door where scatter radiation is exposed

be able to define and know the specifics of a secondary beam

duration of exposure to ionizing radiation

define time

minimize time

know the rule of thumb when dealing with time

space between oneself and the source of ionizing radiation

define distance

intensity of radiation diminishes over distance and commonly applies to radiographers

know why distance is so important and who is commonly applies to

maximize distance

know the rule of thumb when dealing with distance

box shaped device attached to bottom of tube that restricts the x ray beam to the area of interest

define collimator

smaller collimator size = less area exposed, larger collimator size = more area exposed

know the relationship between collimator size and area of exposure

the greater the volume of tissue exposed

know what opportunity increases x ray interactions with matter

photon energy is totally absorbed or scattered

know what 2 things are usually the result of x rays interacting with matter

quality = kvp, quantity = mAs

know which factors control each quality and quantity

the entire x ray beam will be absorbed and contribute to patient dose

know what happens if you don’t have enough penetrating power for beam in regards to patient dose

increasing kvp by 15% will reduce mAs by ½

know the 15% rule

should be limited to 10 days after ovulation

know when it is best to x-ray a female during her child bearing years

greek word atoms meaning indivisible (inseparable/unbreakable)

where does the word atom come from

Democritus’s Theory

Person who developed earliest atomic theory. Hypothesized all things are mad of tiny, invisible structures called atoms. He believed atoms were indestructible and different in size, shape, and structure

John Dalton’s theory

Had scientific evidence that elements combined in definite proportions to form compounds. He theorized that all things were made of atoms and each were unique to each element in their size. He stated compounds were made of molecules made of atoms. He also said a chemical reaction was a rearrangement of atoms

Dmitiri Mendeleev’s theory

advanced Dalton’s work by organizing the known elements into a periodic table

Joseph John thomsons discovery

discovered electrons resulting from the cathode tube. Studied glowing stream of light when electric current passes through negative charged pieces of atoms = electrons

Niels Bohr

made modern atomic theory

The atom is the building block of all matter, atom must have 3 fundamental components: protons, electrons, neutrons

what is the modern atomic theory (2 parts)

protons and neutrons

each atom has a nucleus, what is the nucleus made up of

1 unit of positive charge with a mass of 1.673 × 10^-27 kg

describe a proton

no electrical charge with a mass of 1.675 × 10^-27 kg

describe the neutron

protons have a positive charge

know the difference between the proton and neutron

1 unit of negative charge with a mass of 9.109 × 10^-31 kg

describe the electron

neutrons are neutral they have no charge

know the technical aspect behind a neutral charge atom (what makes it neutral)

atoms charge becomes positive if there are more protons and negative if there are more electrons

know what happens if the balance of an atom is disrupted

when an atom gains an extra electron

define negative ion

atom looses an electron

define positive ion

energy that holds protons and neutrons together in nucleus and creates strong attraction (opposites attract)

define binding energy

measure of amount of energy necessary to split an atom

what bind energy is a measure of

an atom has different energy levels, dependent on distance from nucleus

define electron shells

k outward (k, l, m, n…)

know how each electron shell is letters

Outer shell doesn’t have to be filled but every shell has a limit

know how the electron shell fills

2

know how many electrons the 1st shell can hold

k shell because its closest to nucleus

which shell has the greatest binding energy

the outer shell of the atom

define valence shell

the number of protons and neutrons in nucleus of an atom

define atomic number

the number of protons and neutrons in nucleus of an atom

define atomic mass number

92 ex. oxygen, carbon, chlorine

know how many elements exist in the natural world

water (H2O)

know the most common substance found on earth

elements with atoms with the same number of protons and different number of neutrons

define isotope

elements with atoms with the same number of neutrons and different number of protons

define isotone

elements with atoms that have a different number of protons but same total number of protons and neutrons (atomic mass number)

define isobar

elements with atoms with same number of protons and neutrons but with different amounts of energy within the nucleus

define isomer

7 periods arranged in rows, 8 groups arranged in columns

know how the periodic table is arranged

molecule that contains 2 different elements

define compound

ionic bonding and covalent bonding

what are the 2 primary ways atoms bond

attraction of opposing charges

what is ionic bonding based on

2 atoms that share electrons orbiting the nucleus

what is covalent bonding based on

electromagnetic radiation

an electric magnetic disturbance traveling space at the speed of light with no mass

electromagnetic spectrum

a way of ordering or grouping the different electromagnetic radiations

amplitude

the maximum height of the wave

wavelength

distance between peaks of wavelengths