Final answer:
The most powerful type of nuclear weapon is a thermonuclear bomb, which releases energy through the process of nuclear fusion and is capable of producing far greater yields than fission bombs.
Step-by-step explanation:
The most powerful type of nuclear weapon is a thermonuclear bomb, which is a type of fusion weapon. These weapons are also known as hydrogen bombs or H-bombs. Unlike fission bombs, which use the splitting of atomic nuclei to release energy, thermonuclear weapons use the process of nuclear fusion, where light atomic nuclei combine to form heavier nuclei, releasing an immense amount of energy in the process. The first thermonuclear weapon was detonated on October 31, 1952, and demonstrated the massively increased power of fusion over fission, with a yield of 10 megatons, roughly 670 times that of the bomb which destroyed Hiroshima.
Thermonuclear weapons use a fission bomb as a trigger for the fusion reaction. High-energy neutrons produced in the fission reaction aid the fusion process, potentially allowing for an unlimited energy release. The energy yields of nuclear weapons are measured in kilotons (kT) or megatons (MT) of equivalent conventional explosives, with thermonuclear weapons producing far more thermal output and nuclear radiation than fission bombs or conventional explosives.