surely in an ideal situation (such as an exam question - which is one of the things I am working towards) they may ask the basic questionCould you tell the difference by looking?
The con and des terms are only approximate, aren't they? Certainly only useful for arm waving or, sometimes, for finding a minimum / null in interferometry etc.. What is really relevant is the actual value.
If they are from non-coincident sources you would, in fact, be producing a two slits interference pattern.
"Wave A and B are 10 degrees out of phase. When they superimpose would we get a constructive or deconsrtuctive interferance pattern. Explain"
In this case would the following answer suffice
"They would interfere constuctivley as the total displacement is greater than that of both individual waves".
Maybe i was confusing myself by using the value 1 degree. It would actually ONLY make sense if deconstructive intferferene took place at 180 degrees out of phase, right?
Reason being that this is the only stage where maximum displacement is less than that of either / both waves individually?