What is the atomic bomb used for?

Answer 1

The atomic bomb was used to end the war between the U.S. and Japan. The U.S. also dropped it to test the bomb to see if it worked. When the bomb passed the test the U.S. told Japan that we will drop an atomic bomb; Japan refused to surrender and we dropped two bombs on them (Hiroshima and Nagasaki); that's when Japan surrendered.

In modern terms, atomic bombs (and all nuclear weapons) are political tools, with very little practical battlefield use. In some regards, they can be considered a "terror" weapon, as possession of nuclear weaponry provides the owner with a credible threat to wreck mass destruction upon an opponent. That is, the utility of nuclear weapons comes not from their use, but from the threat of their use. As such, they are classic political tools for use in international power relations.