The model of the atom Thomson. (cupcake model)

The positive charge of the atom occupies the entire volume of the atom and divided this volume with a constant density, electrons are inside.

Model of atom Rutherford. (planetary model)

In the center is the positively charged nucleus, in which is concentrated the whole mass, and the electrons orbit around the nucleus. Overall the atom is electrically neutral.

Postulates Of Bohr.

The first postulate. An atomic system can be only in particular stationary, or quantum, States, each of which corresponds to a certain energy TUS in a stationary state the atom does not radiate.
The second postulate. At the transition of the atom from one stationary state to another is emitted or absorbed a quantum of electromagnetic energy.

Laser (light amplification through stimulated emission of radiation) – a quantum generator of electromagnetic waves in the visible range of light.

• Lasers able to create a very narrow beams of light with an angle of divergence of about 10 -5 rad.
• Laser light has the exclusive monochromaticity. The phase of the wave does not experience irregular changes.
• Lasers are the most powerful sources of light.

The devices of registration and observation of elementary particles:

• 1) gas-discharge Geiger;
• 2) the cloud chamber 1912 G.;
• 3) bubble chamber 1952. Glazer;
• 4) a method of thick-layered emulsions.

Radioactivity was discovered in February 1896 g. Henri Becquerel. Rutherford was discovered, what radiation is of the three types of radiation: particles the nucleus of a helium atom; particles electrons; radiation hard electromagnetic radiation.

Isotopes – particles, with the same nucleus charge (the number of protons), but having a different number of neutrons in the atom.

The unit of activity of radioactive drugs – (Curie) – equal activity of the isotope, when 1C occurs 3,7 10-10decays. The impact of radiation on living organisms is characterized by the radiation dose. If the total charge of ions of one sign produced by radiation in 1 kg of air, equal 1 TC, the radiation dose is equal 1 C/kg. The radiation dose is measured in roentgen.

Dose, per unit time, is called the dose rate. (x-ray/h - R/h, R/min, p/s). The absorbed radiation dose is measured in rad (happy). To account for the different biological effects of any kind of radiation, you enter the unit - roentgen equivalent (REM)