# Why must the plane of polarization be the same for two waves to interfere?

While solving a problem that involved both the concepts, I stumbled upon the following fact, but I cannot somehow visualize the idea. Could anyone please give me some intuition as to why the above stated fact holds?

• Er ... you can get partial interference for incident sources which have difference in polarization that is neither $0$ now $\pi/2$. Apr 9, 2016 at 23:54