USA HISTORY

Detailed explanation-1: -Einstein’s 1939 letter helped initiate the U.S. effort to build an atomic bomb, but work proceeded slowly at first.

Detailed explanation-2: -Robert Oppenheimer. A theoretical physicist and professor of physics at the University of California, Berkeley, Oppenheimer became involved early in the scientific research that ultimately led to the Manhattan Project.

Detailed explanation-3: -The Manhattan Project was a research and development undertaking during World War II that produced the first nuclear weapons.

Detailed explanation-4: -According to Truman and others in his administration, the use of the atomic bomb was intended to cut the war in the Pacific short, avoiding a U.S. invasion of Japan and saving hundreds of thousands of American lives.

Detailed explanation-5: -Contents. The Manhattan Project was the code name for the American-led effort to develop a functional atomic weapon during World War II.