Ionizing Radiation Flashcards
what is matter
anything that has mass and occupies a space
what is the basic unit of all matter
the atom
what does a nucleus consists of
protons and neutrons
what does the atomic number represent
- number of protons
- same as # of electrons in a neutral atom
how many protons does Ca have (atomic number is 20)
20
what is atomic mass
number of protons + neutrons
what is the closest shell letter to outermost
K -> Q
what is the binding energy
the amount of energy required to remove an electron from its shell
what is binding energy measured in
electron volts
how is the electron binding energy related to the atomic number
the more protons -> electrons are more tightly bound
what is ionization
process of forming a positive and negative ion by removal of an electron from an neutral atom
to ionize an atom we need:
sufficient external energy to overcome the electrostatic forces and free the electron
what is radiation
the transmission of energy through space and matter
what are the two forms of radiation
wave theory or quantum theory
what does the wave theory explain
the propagation of radiation
what does the quantum theory explain
the interaction of radiation with matter
explain the waves theory
propagation of radiation in from of waves- no mass- traveling at the speed of light
- electromagnetic radiation
what is wavelength
distance between two successive crests
what is frequency
number of wavelentgh passing a particular point in time
high energy radiation =
high frequency, short wavelength
low energy radiation:
low frequency, long wavelength
what of electromagnetic spectrum is non ionizing
radio waves
- microwaves
- infared radiation
- visible light
- most of UV
what part of the electromagnetic spectrum is ionizing
X rays and gamma rays
- some of UV
red in visible light spectrum is _____ energy
lower
what is the quantum theory
considers radiation as small discrete bundles of energy called photons
each photon has:
mass, energy and travels in straight lines at the speed of light
in the quantum theory particles are
electrically charged
in the quantum theory whats the relationshiip between energy, wavelength and frequency
energy is directly proportional to frequency and inversely proportional to wavelength
what is ionizing rate
- linear energy transfer (LET)
- rate of loss of energy from a particle as it moves through matter
what does ionizing rate depend on
velocity, charge and size
lower velocity, higher charge and bigger size -> ______ LET
greater
what does higher LET mean
less penetration because they lose their energy after short distances
what has high LET
alpha particles
what has low LET
x rays
what are X rays
weightless packages of pure energy without an electrical charge which travels in waves with a specific frequency and wavelength at the speed of light and are able to ionize matter
what are the properties of Xrays
- invisble, weightless, no electric charge
- travels in straight lines
- travels at the speed of light
- highly penetrating
- differentially absorbed by matter
-can ionize matter
-produce biological changes
what is excitation
- when energy transferred is not sufficient to overcome binding energy and electron is not ejected
- receiving electron is raised to higher energy level within the orbit. give up this excess energy and returns to ground level
