Previous Year Question
The costliest metal of the world discovered recently, is
Endohedral Fullerene
Californium 252
Tritium
Rhodium
Correct Answer: B
Detailed Solution
Californium (Cf) is a synthetic and highly radioactive element. Its atomic number is 98, and it belongs to the Actinide series of the periodic table.
Californium was discovered in 1950 at the University of California, Berkeley. It was named after the State of California and the University of California.
Californium-252 (Cf-252) is an important radioactive isotope of californium with a half-life of about 2.645 years. Its most important characteristic is its intense neutron emission.
Cf-252 is mainly used as a neutron source in applications such as—
nuclear reactor start-up, neutron activation analysis, oil-well logging, industrial scanning and specialized scientific applications.
Its production is extremely complex and only very small quantities are produced. A historical account from Oak Ridge National Laboratory placed the cost of Cf-252 at about US$27 million per gram.
It should be remembered that Californium is the element, whereas Cf-252 is its radioactive isotope.