1. The problem statement, all variables and given/known data "Using the two-dimensional wave interference pattern shown and the two equations involving path difference, complete the following. a) i) measure the wavelength of the waves, ii) the distance between sources, and the iii) path distance from each of the sources to the nodal point shown on the diagram. iv) Show the complete calculation for wavelength b) Show the complete calculation for wavelength of the antinodal point shown on the diagram 2. Relevant equations http://www.flickr.com/photos/100153549@N06/9487690991/ (source- another student) lPnS1-PnS2l =(n-1/2)λ lPnS1-PnS2l = mλ 3. The attempt at a solution I am having problems here. a) i) Wavelength of waves = 8 mm *I measured this crest to crest vertically from the source points- Is this right? ii) Distance between sources is 13mm iii) nodal point 1 (top): P1S1= 36.5 mm P1S2= 44.5 mm anodal point 2 (bottom): P2S1= 40 mm P2S2= 34 mm iv) nodal point 1, n=2 l PnS1-PnS2 l =(n-1/2)λ l 40 mm-34 mm l= 1.5λ ∴ λ= 6/1.5mm= 4mm anodal point 2 (bottom): nodal point 2, m=1 lPnS1-PnS2l =mλ l 40 mm-34 mm l= (1)λ ∴ λ= 8mm Okay, so I know that for iv) the answers are not correct. As any point on the second nodal line the path difference (in lamda) will always be n-0.5= 2-0.5= 1.5 λ, but my answer is 40mm-34mm/8 = 0.75 λ And... for any point on the first anoidal line, the path difference (in lamda) should be mλ= 1λ, where my answer is 6λ. Can someone please help explain where I am going wrong? Thank you for your time.