Ch. 2 Basic Physics Flashcards
What are the three standards of measurement?
Time
Length
Mass
What is the standard unit of time?
Seconds
What is the standard unit of length?
Meter
What is the standard unit of mass?
Kilogram
How is speed expressed mathmatically?
length divided by time
How is density expressed mathmatically?
mass over volume
How is volume expressed mathmatically?
by cubing a length or mass divided by a length
What does E=mc2 tell us?
that mass and energy are interchangeable and that every mass has an energy equivalent and every energy has a mass equivalent
What is a force?
anything that exerts a push or a pull on something
What are the four fundamental forces?
- gravity
- the weak nuclear force
- electromagnetism
- the strong nuclear force
What is electromagnetism?
It encompasses all electrical and magnetic phenomena
Describe a weak and strong nuclear force.
a weak nuclear force is responsible for the radioactivity Becquerel discovered in some materials, and a strong nuclear force holds protons and neutrons within the nucleus of an atom.
How is the strength of a force measured?
By how small a particle it can affect. Gravity being the weakest and a strong nuclear force being the strongest
What is the metric system throughout the world known as?
System International or SI System
What are all of the unit conversions is the SI system based on?
multiples of 10
prefix- kilo
k… km=kilometer…10’3…thousands
prefix- mega
M… MV=megavolts…10’6…millions
prefix- giga
G…GHz=gigahertz…10’9…billions
prefix- tera
T… TB=terabytes…10’12…trillions
prefix- centi
c…cm=centimeter…10’-2…hundreths
prefix- milli
m…ms=millisecond…10’-3…thousandths
prefix- micro
u…um=micrometers…10’-6…millionths
prefix- nano
n…nm=nanometers…10’-9…billionths
What does the negative exponent represent in each term?
it expresses the term as a fraction as in millionths billionths etc
All kinds of electromagnetic radiations consist of ripples, similar to water waves, describe these.
it takes one crest or peak and one trough or dip to make up a single wavelength
What is the measuring unit used for wavelengths on an x-rays?
Angstrom
What is the general unit for energy?
a joule
Describe a joule.
One joule is roughly enough energy to get a one lb object moving about 10 miles per hour.
Describe matter converting to energy.
When matter is converted to energy it takes an infinitesimal amount of matter to produce incredible power.
Describe converting energy to matter.
An enormous amount of energy is needed to produce even the smallest particle.
What is rest energy?
The energy that a particle would release if it were annihilated or changed into pure energy
What are the 6 forms energy can take?
- Mechanical Energy
- Chemical Energy
- Electrical Energy
- Thermal Energy
- Electromagnetic Energy
- Nuclear Energy
What is a transducer?
Any device that can change one form of energy into another
What two classifications can Mechanical Energy be divided into?
- Potential Energy
- Kinetic Energy
What is kinetic energy?
- the energy of motion
- represented by the actual speed
What is potential energy?
- the energy of position
- represented by the potential to speed up
Describe the Law of Conservation for Mechanical Energy.
The sum of an objects kinetic energy and its potential energy must always add up to the same amount, but the two can trade off.
What do all forms of energy eventually degenerate into?
heat energy
What is quantum physics?
The study of all the interactions and relationships between the atom and waves of radiation.
The intensity of radiation incident upon the surface of an object is its what?
Exposure
Exposure is best detected as an ionization in the air just above the surface and generates an electrical charge in a what?
A detecting device
What does ESE stand for?
Entrance skin exposure
The intensity of radiation entering through the surface of the body is what?
The entrance skin exposure
What are the conventional units used in X-ray?
Roentgen
RAD
Rem
What does RAD stand for?
Radiation absorbed dose
What does Rem stand for?
Radiation equivalent in man
This is the unit of absorbed dose applied to all radiation?
The Rad
This is the unit of dose equivalent of true biological harm.
Rem
This is the only unit for measuring intensity of raw X-ray beams emitted by the X-ray tube at a particular distance.
Roentgen
1 roentgen is equivalent to how many ion pairs?
2.08x10’9
What are two weighted factors used to derive rem from rad?
Wr- relative harmfulness or radiation
Wt- relative sensitivity of exposed tissue compared to other tissue
