Diffraction in a paraffinWatch
So I was answering this question, got stuck and looked at the hint video. I understood everything apart from the part where he says "In this case, d = 1/2 wavelength". https://youtu.be/fXB5txi90h0?t=35
Can anyone explain this to me? And also why can I not use the wavelength given in the question for wavelength = speed/frequency?
you could think of a standing wave being made of two travelling waves going in opposite directions - so they're meeting each other at twice the speed that each waves travels through the media at.
or see https://spark.iop.org/standing-waves