Can you give me some examples, link of correspondence principle use in life. All I have found out are theoretical examples such as Bohr's model... If I understand right, correspondence principle says that simple equations used for classical examples with a few data and quantum equations used for larger data, give us pretty much the same results. If we'd use simple equations instead of quantum we'd make some mistake, but not to critical. Is my thinking correct? Can you give me an example for its use in industry?