week 2: electromagnetic radiations Flashcards
define energy
ability to do work
name some common classifications of energy
mechanical
thermal
chemical
nuclear
electrical
EM
electromagnetic energy: an electric and magnetic ________ traveling through ____ at the _________
disturbance, space, speed of light
what is the EM spectrum?
The range of electromagnetic energy in wavelengths. It is a continuum of every possible electromagnetic frequency.
Radio waves, light, and x-rays are all examples of different ranges of wavelengths within this spectrum.
distance traveled in completing one cycle
wavelength
number of cycles per second (Hz)
frequency
what type of wave is a wavelength?
sine wave
EM energies varies in _____
kinetic energy
what is the velocity of EM radiation (powerpoint?)
186,000 miles/second
for EM radiation, _______ is constant; __________ vary
velocity, wavelength and frequency
distance between crest and trough
amplitude
what is radiation?
energy that passes from one location to another
what determines which types of radiation will be ionizing?
kinetic energy of the radiation
what is difference between ionizing and nonionizing radiation?
the able to interact with matter and remove electrons
When we ionize an atom, we create _________
an ion pair
particulate radiation (is/is not) ionizing radiation
is
photons are the ______ of electromagnetic energy
smallest possible unit
what are the 4 characteristics of photons?
- Travel through space at the speed of light
- No mass
- Surrounded by electric and magnetic fields
- Move in a sine wave configuration
what is a photon?
smallest possible unit of EM energy
particulate radiation includes
alpha and beta particles
what’s the difference between x-ray photon and photons?
photons can be light photons, microwave photons; x-ray photons are ionizing
What are the characteristics of x-ray photons?
-travel in straight lines at 186,000 miles/sec
-have no mass
-are highly penetrating and invisible
-are electrically neutral
-can cause harmful biologic effects
-cannot be detected by human senses
-polyenergetic or heterogenous energies
-can cause ionization
-produce secondary and scatter radiation
A measure of the energy of a moving electron or x-ray photon
electron volts
The process of turning an atom into an ion by adding or removing an electron.
ionization
The quality of a structure that is denser and, therefore, absorbs x-rays more readily.
radiopaque
The condition in which some electromagnetic radiation photons (such as light or x-rays) are absorbed but some are transmitted through a substance.
attenuated
The principle that the intensity of electromagnetic radiation such as light or x-rays diminishes by a factor of the square of the distance from its source
inverse square law
The state of light or x-ray photons that have passed through a substance such as air, clear glass, or different substances in the patient’s body. This is wave characteristic
transmission
Bending” of light rays as they pass through one clear medium to another. The amount of refraction varies, depending on wavelength. This is wave characteristic
refraction
do x-rays have a charge?
no, they are electrically neutral
wave-particle duality: Ability of EM radiation to exhibit properties of a _______ depending on its _____ (and sometimes its _________)
particle or wave; energy, environment
originate differences in x-ray v. gamma rays
gamma: originate in the nuclei of atoms
x–ray: originates from interaction between electrons and atoms.
gamma originate in the _______
nuclei of atoms
x-rays originate in the _____________
interaction between electrons and atoms
is the energy in the x-ray beam heterogenous or homogeneous?
heterogeneous
