Thomas Edison observes Thermionic emission.

Thermionic emission is a phenomenon where electrons are emitted from a heated surface or material. This emission occurs when the thermal energy of the material is sufficient to overcome the electrostatic forces holding the electrons in place, allowing them to escape into the surrounding space. The emitted electrons can form an electric current if collected by an anode or positively charged electrode placed nearby.

Electron Cloud Formation: When a material is heated, the thermal energy causes its electrons to gain kinetic energy, increasing their motion within the material. Some electrons near the surface can gain enough energy to overcome the attractive forces of the material’s atoms or molecules and escape into the surrounding vacuum.

Work Function: The likelihood of electron emission depends on the material’s work function, which is the minimum energy required for an electron to escape the material’s surface. Materials with lower work functions are more likely to exhibit thermionic emission.

Richardson’s Law: Richardson’s law describes the rate of thermionic emission and is given by the Richardson-Dushman equation. It states that the current density (J) of thermionically emitted electrons from a surface is proportional to the temperature (T) of the surface and inversely proportional to the square of the surface’s work function (?).

Applications:
Vacuum Tubes: Thermionic emission is the principle behind the operation of vacuum tubes, which were extensively used in early electronic devices such as radios, televisions, and amplifiers.
Electron Microscopes: Thermionic emission is utilized in electron microscopes, where a heated cathode emits electrons that are accelerated and focused to produce high-resolution images of samples.
X-ray Tubes: In X-ray tubes, electrons emitted via thermionic emission are accelerated and directed towards a target material, generating X-rays through interactions with the target.

Cold Cathodes: While thermionic emission typically involves heated cathodes, there are also instances of cold cathode emission, where electrons are emitted at room temperature through mechanisms such as field emission or secondary electron emission.

Israel obtains four of the seven Dead Sea Scrolls.

German reunification: An agreement is reached on a two-stage plan to reunite Germany.

Israel obtains four of the seven Dead Sea Scrolls.

Israel obtains four of the seven Dead Sea Scrolls.
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Israel obtains four of the seven Dead Sea Scrolls.

On February 13, 1955, Israel’s prime minister, Moshe Sharett, held a press conference to announce that the country had acquired four more of the fabled Dead Sea Scrolls, an acquisition of sterling importance to scholars of ancient Judaism and early Christianity and a real coup for the fledgling state’s national pride.

The initial discovery of what came to be known collectively as the Dead Sea Scrolls — referring to whole documents and fragments of some 950 parchment scrolls, dating to the period between the 3rd century B.C.E. and the 1st century C.E. — was in 1946. That’s when three Bedouin of the Ta’amra tribe happened upon the first part of a cache of seven rolled-up pieces of parchment, stored for over 2,000 years in clay jars in a cave in the hills overlooking the western shore of the Dead Sea, adjacent to the site known as Qumran, north of Ein Gedi.

Israel gets four of the seven Dead Sea Scrolls.

On February 13, 1955, Israels prime minister, Moshe Sharett, held a press conference to announce that the country had acquired four more of the fabled Dead Sea Scrolls, an acquisition of sterling importance to scholars of ancient Judaism and early Christianity and a real coup for the fledgling states national pride.

The initial discovery of what came to be known collectively as the Dead Sea Scrolls — referring to whole documents and fragments of some 950 parchment scrolls, dating to the period between the 3rd century B.C.E. and the 1st century C.E. — was in 1946. Thats when three Bedouin of the Taamra tribe happened upon the first part of a cache of seven rolled-up pieces of parchment, stored for over 2,000 years in clay jars in a cave in the hills overlooking the western shore of the Dead Sea, adjacent to the site known as Qumran, north of Ein Gedi.

The Bedouin quickly recognized that these artifacts might be of significant historical value. One of the antiquities dealers with whom they consulted was in touch with an archaeologist at the American School of Oriental Research, today the Albright Institute, in Jerusalem. This contact soon led to a scientific expedition which surveyed a number of the caves in the area, in search of additional documents and information about the finds.

Unknown apocalyptic text

In December 1947, as the clouds of war were gathering over the region, Eliezer Lipa Sukenik, professor of archaeology at the Hebrew University, succeeded in purchasing three of those seven scrolls from a dealer in Bethlehem. They included a partial manuscript of the biblical Book of Isaiah, and two scrolls that were dubbed the Thanksgiving Scroll, and the War of the Sons of Light against the Sons of Darkness.

Israel obtains the Dead Sea Scrolls.

Israel gets four of the seven Dead Sea scrolls.