Final answer:
Plasma arcs can reach extremely high temperatures, up to 15,000,000 Kelvin or more. They are created through fusion reactions or through the explosion of a nuclear fission bomb. Plasma arcs have many practical applications.
Step-by-step explanation:
Plasma arcs can reach extremely high temperatures. Useful fusion reactions require temperatures of about 15,000,000 Kelvin or more, where all molecules dissociate into atoms and form plasma. In thermonuclear weapons, temperatures high enough for fusion are achieved through the explosion of a nuclear fission bomb. Plasma arcs can be used in various applications such as plasma cutting and plasma televisions.