Multiple choice general knowledge science & technology Atomic bomb detonated on Hiroshima was...... Fat man Little boy Fat boy Little man Reveal answer Fill a bubble to check yourself B Correct answer Explanation The atomic bomb dropped on Hiroshima on August 6, 1945 was code-named 'Little Boy.' The bomb dropped on Nagasaki on August 9, 1945 was called 'Fat Man.' Little Boy used uranium-235 while Fat Man used plutonium.