Timeline: Nuclear Treaties & Agreements

1963 Limited Test Ban TreatyAn agreement between the US, USSR, and UK which prevented nuclear testing above ground, underwater, and in outer space. But it does allow testing to occur underground as long as the radioactive fallout is not widespread. A total of 116 countries have signed this, and China, who had not signed, did testing in 1992 that violated the treaty's guidelines.

Chronological Developments in Nuclear Physics

1890s
1895
November 8 - Wilhelm Roentgen discovers X-Rays
1897
Becquerel and Marie Curie discover radioactivity
1895 - 1899
Ernest Rutherford discovers alpha and beta radiation
1898
Marie and Pierre Curie isolated the two new chemical elements polonium and radium

Atomic and Nuclear Physics

Atoms - Atoms are the smallest unit of an element that chemically behaves the same way the element does. When two chemicals react with each other, the reaction takes place between individual atoms at the atomic level.

Atomic Structure

• In the early 20th century, a New Zealand scientist working in England, Ernest Rutherford, and a Danish scientist, Niels Bohr, developed a way of thinking about the structure of an atom that described an atom as looking very much like our solar system.
• An atom is composed of three basic particles – electrons, protons and neutrons.
• Nucleus of an atom consists of protons and neutrons.
• Electrons revolve in atomic orbit.

Magnetism

Magnetism - Magnetism is a force of attraction or replusion that acts at a distance. It is due to a magnetic field, which is caused by moving electrically charged particles or is inherent in magnetic objects such as a magnet.

Magnetism - A magnet is an object that exhibits a strong magnetic field and will attract materials like iron to it. Magnets have two poles, called the north (N) and south (S) poles. Two magnets will be attacted by their opposite poles, and each will repel the like pole of the other magnet. Magnetism has many uses in modern life.

Current Electricity

Electric Current - The Electric current is a flow of electric charge through a conductive medium.

In electric circuits this charge is often carried by moving electrons in a wire. It can also be carried by ions in an electrolyte, or by both ions and electrons such as in a plasma.

The SI unit for measuring the rate of flow of electric charge is the ampere, which is charge flowing through some surface at the rate of one coulomb per second. Electric current is measured using an ammeter.

Static Electricity

Static electricity is an excess of electric charge trapped on the surface of an object. The charge remains until it is allowed to escape to an object with a weaker or opposite electrical charge, such as the ground, by means of an electric current or electrical discharge. Static electricity is named in contrast with current electricity, which flows through wires or other conductors and transmits energy.

Light

Light is a type of energy which propagates as electromagnetic waves. In the spectrum of electromagnetic waves, light has place between ultraviolet and infrared region.

Some Facts About Light

•    Electromagnetic waves are transverse waves, therefore, light is also transverse wave.
•    Wave nature of light explains; rectilinear propagation of light, reflection of light, refraction of light, interference of light, diffraction of light and polarization of light.
•    The happenings in physics like Photoelectric Effect and Compton Effect can not be explained on the basis of wave nature of light. These phenomenons are explained on the basis of quantum theory of light, explained by Albert Einstein.
•    The quantum theory of light, considers light as a packet or bundle of energy, these energy packets are called photons. Photon associates with it as Energy E; where E = hv
•    Light has dual nature and behaves as a particle as well as wave.
•    Speed of Light was first calculated by Roemer in 1678 AD.
•    Speed of light is maximum in vacuum, which is equivalent to 3x108 m/s.