"Coulomb's Law"

What is Coulomb's Law?

Coulomb's law, developed by Charles Augustin de Coulomb, may be stated as follows:
The magnitude of the electrostatic force between two points electric charges is directly proportional to the product of the magnitudes of each charge and inversely proportional to the square of the distance between the charges.

Electrical force also has a magnitude or strength. Like most types of forces, there are a variety of factors which influence the magnitude of the electrical force. Two like-charged balloons will repel each other and the strength of their repulsive force can be altered by changing three variables. First, the quantity of charge on one of the balloons will affect the strength of the repulsive force. The more charged a balloon is, the greater the repulsive force. Second, the quantity of charge on the second balloon will affect the strength of the repulsive force. Gently rub two balloons with animal fur and they repel a little. Rub the two balloons vigorously to impart more charge to both of them, and they repel a lot. Finally, the distance between the two balloons will have a significant and noticeable affect upon the repulsive force. The electrical force is strongest when the balloons are closest together. Decreasing the separation distance increases the force. The magnitude of the force and the distance between the two balloons is said to be inversely related.

The quantitative expression for the affect of these three variables on electric force is known as Coulomb's law. Coulomb's law states that the electrical force between two charged objects is directly proportional to the product of the quantity of charge on the objects and inversely proportional to the square of the separation distance between the two objects. In equation form, Coulomb's law can be stated as

where:
F=is the magnitude of the force exerted,
q1=is the charge on one body,
q2=is the charge on the other body,
r=is the distance between them,

k=9.0 x 109 N • m2 / C2 (constant)

"Resistor"

What is a Resistor?
A resistor is a two-terminal electrical or electronic component that resists an electric current by producing a voltage drop between its terminals in accordance with Ohm's law: R= V divided by I, The electrical resistance is equal to the voltage drop across the resistor divided by the current through the resistor. Resistors are used as part of electrical networks and electronic circuits.

This is an example of a Resistor:


The second standard is the use of the resistor colour code. Modern resistors can be very small & there might be hundreds of them on a circuit board, pointing in all sorts of directions. Trying to find or read printed values in this situation would something of a nightmare! To avoid this problem, resistors normally display their value as a series of coloured bands or rings. These use colours as indicated in figure 2.3. These are read starting with the band nearest an end. Most resistors have just four bands. The first two give the significant figures. The third gives a power of ten which you multiply the figures by to get the correct resistance. The fourth band (which isn't always there!) gives the tolerance or accuracy of the value. Some resistors have extra bands, but we won't worry about that in this course!

"Properties of Ionizing Radiation"

Types of Radiation ALPHA BETA GAMMA
CHARGES +2, -1, 0
MASS 4, 1/2000 , 0
COMPOSITION 2PROTONS 2NEUTRONS , same as an electron, burst frequency wave
SPEED slow, fast, very fast
PENETRATING POWER low, medium , high
IONIZING POWER high, medium, 0

"The Nuclear Symbol"

The nuclear symbol consists of three parts:
1.)the symbol of the element.

2.)the atomic number of the element.

3.)the mass number of the specific isotope.

*Here is an example of a nuclear symbol: *



The element symbol, Li, is that for lithium.
The three, subscripted left, is the atomic number and the seven, superscripted left, is the mass number.

Here's another:



The atomic number is:
The number of protons in the nucleus of the atom.
The mass number is:
The number of protons and neutrons in the nucleus of the atom.

"Four Fundamental Forces"

There are Four Specific fundamental forces acting in the nucleus of an atom, these are:
1.)Gravitational forces- which is for the mass.
2.)Electrical forces- which is for the different charges.
3.)Strong forces- which is for the distance.
4.)Weak forces- which is for attraction.

"Henri Becquerel"

Antoine Henri Becquerel :

while investigating phosphorescence in uranium salts, Becquerel accidentally discovered radioactivity. Investigating the work of Wilhelm Conrad Röntgen, Becquerel wrapped a fluorescent mineral, potassium uranyl sulfate, in photographic plates and black material in preparation for an experiment requiring bright sunlight. However, prior to actually performing the experiment, Becquerel found that the photographic plates were fully exposed. This discovery led Becquerel to investigate the spontaneous emission of nuclear radiation.

According to him ,One wraps a Lumière photographic plate with a bromide emulsion in two sheets of very thick black paper, such that the plate does not become clouded upon being exposed to the sun for a day. One places on the sheet of paper, on the outside, a slab of the phosphorescent substance, and one exposes the whole to the sun for several hours. When one then develops the photographic plate, one recognizes that the silhouette of the phosphorescent substance appears in black on the negative. If one places between the phosphorescent substance and the paper a piece of money or a metal screen pierced with a cut-out design, one sees the image of these objects appear on the negative. … One must conclude from these experiments that the phosphorescent substance in question emits rays which pass through the opaque paper and reduces silver salts.[
(The picture below is the image of Becquerel's photographic plate which has been fogged by exposure to radiation from uranium salts. The shadow of a metal Maltese Cross placed between the plate and the uranium salts is clearly visible.)

"Radioactive Decay"

What is radioactive decay?
Is the spontaneous random emission of particles from nucleus of the atom.

"Radioactivity and Radioactive"

What is radioactivity?
*Radioactivity is the process where unstable nuclei give off excess energy by emitting particles and electromagnetic radiation.

What are radioactive materials?
*Radioactive materials are substances whose atoms have unstable nuclei.

"Picture of Ionizing Radiation"

"Ionizing Radiation"

There are three specific types of ionizing radiation:
1.)Alpha radiation is a type of radioactive decay in which an atomic nucleus emits an alpha particle (two protons and two neutrons bound together into a particle identical to a helium nucleus) and transforms (or 'decays') into an atom with a mass number 4 less and atomic number 2 less

2.)Beta radiation is a type of radioactive decay in which a beta particle (an electron or a positron) is emitted. In the case of electron emission, it is referred to as "beta minus" (β−), while in the case of a positron emission as "beta plus"

3.)Gamma rays or gamma-ray (denoted as γ) are forms of electromagnetic radiation (EMR) or light emissions of a specific frequency produced from sub-atomic particle interaction, such as electron-positron annihilation and radioactive decay; most are generated from nuclear reactions occurring within the interstellar medium of space. Gamma rays are generally characterized as electromagnetic radiation, having the highest frequency and energy, and also the shortest wavelength, within the electromagnetic spectrum, i.e. high energy photons