RAD 107 FINAL EXAM STUDY GUIDE

ALARA stands for…

As Low As Reasonably Achievable

Mass vs weight

mass - described in an object based on energy equivalence

weight - force exerted on an object by gravity

Energy equivalence equation

E=mc²

Conservation of Energy law

energy can neither be created nor destroyed

Conservation of matter law

matter can not be created nor destroyed

Alpha particle

Particle released during alpha emission, 2 protons 2 neutrons but 0 electrons

Beta particle

“electron” (except from different origin) that emerges from the nucleus during beta decay

Positron

electron with a positive charge

X-rays and gamma rays

electromagnetic waves usually emitted with particles, travels at the speed of light

radiation exposure measured in air

traditional: Roentgen

SI: Gray_a

Medical radiation exposure to a patient, measured in tissue

Traditional: RAD

SI: Gray_t

Occupational exposure to radiation

Traditional: REM

SI: Sievert

Roentgen definition

Unit of radiation exposure in the air, measures using only x-rays and gamma rays

Atoms vs Molecules

atoms are individual units of matter

molecules are groups of 2+ atoms

Radiation definition

Energy emitted and transferred through space

Matter definition

anything that has mass and takes up space

Ionization definition

the removal of an electron from an atom

Energy definition

the ability to do work

Types of energy

potential, kinetic, chemical, electrical, thermal, nuclear, electromagnetic

Inertia definition

property of matter that resists change in motion or at rest

potential vs kinetic energy

potential energy is stored energy of a position or configuration

kinetic energy is the energy associated with the motion of an object

Formula for kinetic energy

KE = ½ mv²

m= mass

v²= velocity squared

final units: kg(m/s)²

Speed

rate at which objects cover distance (rate of change of position)

Acceleration

rate of change of velocity

Acceleration equation

a = (v_t - v_o)/ t

final units: m/s²

Fundamental units of measurement

MKS:

distance = meters

mass = kilograms

time = seconds

Derived units of measurements

made up of fundamental units

acceleration = m/s²

velocity = m/s

force = kg(m/s²)

Work = N (kg(m/s²)) * m = Joules (J)

Momentum

mass x velocity

greater velocity = greater momentum

final unit = kg(m/s²) Newton (N)

Properties of matter

has mass, takes up space

Periods (periodic table)

horizontal rows, determines the number of electron shells an element will have (1-7)

Groups (periodic table)

vertical columns, sorted according to number of electrons in the outer shell of an element (1-8)

Atomic Mass Number

number of nucleons (protons and neutrons) in an element

Atomic Mass Unit

unit of mass of an element based on the mass of the Carbon-12 atom

Atomic Mass

includes the number of protons, neutrons, and electrons

Atomic number

number of protons

Elemental mass

weighted average of all atomic isotopes of an element

Noble/Inert Gases

group 8, completely stable and does not react to other elements, full outer shell

Nucleons

protons and electrons

Binding energies

inner shell has the strongest binding energy

outer shell has the weakest binding energy

charges of subatomic particles

proton = +

neutron = O

electron = -

what determines the chemical properties, number of electrons, and number of protons in an atom?

the atomic number

Alpha particles vs helium atom

alpha particle has 2 protons and 2 neutrons but no electrons

Centripetal force

center seeking force that keeps electrons in orbit

Centrifugal force

outward seeking force, helps electrons maintain distance from nucleus

Formula for maximizing the number of electrons in any shell (excluding outer shell)

2n² (n=period/shell number)

Chemical notation

¹ 1 H (1 proton, 1 neutron, 1 electron)

^19₉ F^- (9 protons, 10 neutrons, 10 electrons) (negative charge = add an electron)

^19₉ F⁺ (9 protons, 10 neutrons, 8 electrons) (positive charge = lose an electron)

neutrons = top number - bottom number

Radioactivity

emission of particles and energy from an atoms nucleus that is unstable (to try and achieve stability)

What type of radioactivity occurs most often

beta emission/decay

Half-life definition

the time it takes for a quantity of radioactive material to be reduced to ½ its original value

Photon vs particle

photons are forms of electromagnetic energy with no mass or charge

particles are the same but posses mass

How much bigger are protons and neutrons than electrons?

2000x

Unit of a quantity of radioactive material

Becquerel = 1 disintegration/second

Speed of light

3.0 × 10⁸ m/s

What fields make up the electromagnetic wave?

electric and magnetic fields

Electromagnetic waves move…

at the speed of light (3.0 × 10⁸ m/s)

Amplitude (waves)

½ the range from crest to valley (or from 0 to crest/valley)

Frequency (waves)

Number of cycles per second

1 Hz = 1 cycle/s

1 cycle = 1 wave

Wavelength (waves)

distance from crest to valley

Wavelength of red light

red = 700 nm

Wavelength of violet light

violet = 400 nm

Where is Planck’s constant used?

used in Planck’s quantum equation: E = hf

E = eV

h = Planck’s constant

f = photon frequency in Hz

What is the relationship of frequency and wavelength in light waves?

Frequency and wavelength are inversely related

The electromagnetic spectrum

(lowest frequency) Radiofrequency — microwaves — infrared — visible light — ultraviolet — x-rays and gamma rays (highest frequency)

Wave equation

Velocity = Wavelength x Frequency

c = λf

How is the wave equation used regarding electromagnetic waves?

velocity is constant and is equal to the speed of light

How is the wave equation used with sound waves?

the velocity varies depending on the density of the material it passes through

density decreases = speed increases

Resistor

inhibits electron flow

Battery

provides electrical potential

Capacitor (condenser)

momentarily stores electric charge

Ammeter

measures electric current

Voltmeter

measures electric potential

Switch

turns circuit on or off by providing infinite resistance

Transformer

increases or decreases voltage by fixed amount (AC only)

Rheostat

variable resistor

Diode

allows electrons to flow only in one direction

Ohm meter

measures resistance

Short circuit

an unintended pathway that allows the current to pass directly across the electric potential instead of through an element that uses the power

Open circuit

a break in a circuit that stops the flow of electrons

Conventional current

Positive to negative terminal, assumes positive electron charged flow

Electron flow

negative to positive terminal, assumes negative electron charged flow

Volts

joules/coulomb

3 ways for electrification

friction - rubbing electrons off one atom onto another

contact - touching an object so the charge transfers

induction - one charged object attracts molecules and cannot freely move

Electrostatics

study of stationary electric charges

Electrodynamics

study of electric charges in motion

Superconductors

materials with no resistance to conduction (niobium and titanium)

Conductors

Any substance where electrons move freely (copper and aluminum)

Semiconductors

materials that sometimes insulate and sometimes conduct (silicon and germanium)

Insulators

materials that do not allow any electron flow (rubber, wood, glass)

Power

electric rate of doing work (measured in Watts)

What it takes to have a current in a circuit

potential difference (voltage) and a closed conducted path

Coulomb’s Law

Electrostatic force increases directly as the product of the two charges increases. Force decreases in an inverse relation with the square of the distance between 2 objects (leads to inverse square law)

F = K (Q1Q2)/D₂

How do electric fields radiate?

Points outward from a positive charge and in towards a negative charge

Ohm’s Law

Potential difference equals the current flow times resistance

V = IR

V= volts

I = electric current in amps

R = electric resistance in Ohms