Nuclear weapon

A nuclear weapon (also known as an atom bomb, an atomic bomb, a nuclear bomb, or a nuclear warhead, and colloquially as an A-bomb or a nuke) is an explosive device that derives its destructive power from nuclear reactions, either fission (fission bomb) or a combination of fission and fusion reactions (combination bomb) (thermonuclear bomb). With just a little quantity of mass, both sorts of bombs may produce enormous amounts of energy.

An amount of energy about equivalent to 20,000 tonnes of TNT was unleashed in the first test of a fission ("atomic") weapon (84 TJ). The first thermonuclear (hydrogen) bomb test unleashed enough energy to detonate nearly 10 million tonnes of TNT, according to estimates (42 PJ). Historically, the W54 and the Tsar Bomba had outputs ranging from ten tonnes of TNT to fifty megatons (see TNT equivalent). It is possible to unleash enough energy to detonate more than 1.2 million tonnes of TNT using a thermonuclear device that weighs little more than 2,400 pounds (1,100 kg) (5.0 PJ).

It is possible to ruin an entire city by explosion, fire, and radiation using a nuclear explosive that is little bigger than a conventional bomb. A major concern of international relations strategy is the spread of nuclear weapons, given that they are weapons of mass devastation. When the United States launched nuclear bombs on the Japanese cities of Hiroshima and Nagasaki in 1945 during World Military II, it was the second time that nuclear weapons were used in a war setting.