In physics, especially in the quatum mechanics, the complementarity is a experimental result (also theoretically predicted) which states that objects have properties that are complementary to each other, but can not be observed or measured all at once. The Complementarity Principle, enunciated by Niels Bohr in 1928, are related to the so-called wave-particle duality: The wavelike and corpuscular behaviors are complementary properties of the same entity.