Of the many theoretical contributions to the quantum theory, one of the contributions was the "uncertainty principle". Which of the following statements describes the essence of this principle?

Electrons exist in discrete energy levels, described by quantum numbers

Energy must be added to move an electron to a level further away from the nucleus and removed to move an electron closer to the nucleus

Radiant energy is quantized

Due to the dual nature of electrons, we cannot simultaneously know an electron's position and its momentum (path). Measuring one changes the other.

Question

Of the many theoretical contributions to the quantum theory, one of the contributions was the "uncertainty principle". Which of the following statements describes the essence of this principle?
		
Electrons exist in discrete energy levels, described by quantum numbers
		
Energy must be added to move an electron to a level further away from the nucleus and removed to move an electron closer to the nucleus
		
Radiant energy is quantized
		
Due to the dual nature of electrons, we cannot simultaneously know an electron's position and its momentum (path). Measuring one changes the other.

australopithecus · Answer

http://en.wikipedia.org/wiki/Uncertainty_principle The fist paragraph should help you answer this