Your IRS Electronic Filing Identification Number (EFIN) does not expire. Your IRS Preparer Tax Identification Number (PTIN) does expire every tax season. PTIN renewal occurs after October 15, and the identification number is valid through December 31 of the following year.
atomic bomb or A-bomb, weapon deriving its explosive force from the release of nuclear energy through the fission (splitting) of heavy atomic nuclei.The first atomic bomb was produced at the Los Alamos, N.Mex., laboratory and successfully tested on July 16, 1945.tomic bombs were subsequently developed by the USSR (1949; now Russia), Great Britain (1952), France (1960), and China (1964). A number of other nations, particularly India, Pakistan, Israel, and North Korea now have atomic bombs or the capability to produce them; South Africa formerly possessed a small arsenal.
Hiroshima, Japanese city, situated some 8M km. (500 mi.) from Tokyo, on which the first operational atomic bomb was dropped at 0815 on 6 August 1945. Nicknamed 'Little Boyââa reference to Rooseveltâthe bomb was 3 m. (9 ft. 9 in.) long, used uranium 235, had the power of 12.5 kilotons of TNT, and weighed 3,600 kg. (nearly 8,000 lb.).