1. Chapter 3: Electrostatics and Energy, Magnetism and Electricity

2. Matter vs. Energy The substance that comprises all physical objects.
Mass
The ability to do work
Motion
Matter can become energy and energy can become matter
Neither can be created or destroyed

3. Types of Energy Mechanical Chemical Thermal Nuclear Electromagnetic
Ex:
Chemical
Thermal
Nuclear
Electromagnetic
Electrical

4. Organization of Energy
How much energy can we see?
Important in ordering film and developing a dark room

5. Waves vs. Particles Energy is described as an endless wave
The waves can be long and low OR high and frequent.
The distance between each individual crest is called the wavelength.
The pace at which the waves travel is called the frequency.
The symbol for frequency is Hz.
Energy and frequency are directly proportional

6. Particles vs. Waves
High frequency energies, such as x-rays or gamma rays, act more like individual particles than like waves.
These particles are called photons.
Photon energy depends on frequency.
Directly proportional

7. Roentgen’s Properties of X-Rays
Highly penetrating & invisible rays that are a form of electromagnetic radiation
Electrically neutral
Can be produced over a wide range of energies & wavelengths
Release small amounts of heat when passing through matter
Travel in straight lines
Travel at the speed of light
Can excite or ionize atoms
Cause certain crystals to emit light
Cannot be focused by a lens
Produce a latent image on photographic film
Produce chemical & biological changes in matter
Produce scattered & secondary radiation

8. Electricity: the movement of electrons
Remember the composition of an atom?
How tight are the bonds of electrons?
What charge does an atom have when an electron abandons it?
Free electrons leave an atom and float in space
Accumulating free electrons creates a ___________ charge.
*This is how radiation is produced
in an x-ray tube

9. Laws of Electrostatics
Like charges repel; unlike charges attract
Happens in the x-ray tube right before exposure
Inverse Square Law:
The intensity of the x-ray beam is inversely proportional to the square of the distance from the source.
½ the distance, intensifies the radiation by 4 times

10. Laws of Electrostatics
3. Distribution
Charges reside on the outside of conductors, but all through non-conductors.
4. Concentration
The greatest concentration of charges is on the surface where the curve is the greatest.
5. Movement
Only negative charges move
along conductors.

11. Electrification An object can be electrified in three different ways:
Contact: Law 3 + Law 4 because of Law 1
Friction: electricity occurs because one object is rubbed against another.
Ex: Running a comb through dry hair builds up free electrons in the hair (thanks Law 1)
Note: In these two way, both forces had to touch each other

12. Electrification
3. Induction: uses the force field of the electrons of one object to cause a reaction in the opposing object without any contact.
This energy and the power of it’s effect, is what we use in x-ray tubes.

13. Conductors
Objects that conduct electricity well

14. Insulators
Objects that do not conduct electricity very well, if at all.

15. Electric Current Groups of electrons flowing past a point in time.
Unit of current is the Ampere
Milliamperes (mA) are used to regulate the number of electrons used to produce x-ray photons.
mA is directly proportional to the density of the image
Ex. Increasing the mA will darken an image/increase the density.
Decreasing the mA will decrease the density/lighten the image.

17. Resistance Reduces the amount of current flow.
The ohm is a unit of resistance.
Ex: Garden hose vs. water hose

18. Potential Difference
Causes electrons to travel from one end of a wire to the other.
The force that draws the electrons from an area of excess at one end of the circuit to an area deficient of electrons at the other area of the circuit.
Unit of measure is the volt
Voltage tells us the strength of the electron flow