A great physicist by the name of Richard Feynman said, "I think it is safe to say that no one understands quantum mechanics." What do you think he meant by this? Does this mean quantum mechanics is wrong? How can we know?

Why are alpha and beta rays deflected in opposite directions in a magnetic field? Why are gamma rays not deflected at all? Why are alpha particles with the same velocity deflected less than beta particles?

Explain fully one pro and one con of nuclear energy.