What was the atomic bomb used for when invented?

Answer 1

• when leo szilard invented the neutron chain reaction in 1933 it was used for nothing as it could not yet be built. his 1934 patent on it suggests using it as a more efficient way to transmute elements, other possible uses mentioned were atomic bombs and power reactors.
• it was not until 12 years later in 1945 after spending 2 billion dollars (mostly on industrial infrastructure) that the US was able to begin building atomic bombs.
• after testing one atomic bomb on july 16, the next 2 atomic bombs were used as weapons in combat against Japan on august 6 and 9. ending ww2.