Albert Einstein ( 14 march 1879- 18 april 1955) was a German-born theoretical physicist who discovered the theory of general relativity, effecting a revolution in physics. For this achievement, Einstein is often regarded as the father of the modern physics. He received the 1921 Nobel Prize in Physics for his services to theoretical physics, and especially for this discovery of the law of the photoelectric. He is also the author of the famous formula E= mc² that is the formula of the atomic bomb.