hello again folks, this is the last problem that I haven't gotten in this week's homework. see attached image.
1. Homework Statement
Two rectangular pieces of glass (see attached image, I painstakingly made it with a very fussy/crashey program) are laid on top of one another on a plane surface. A thin strip of paper is inserted between them at one end, so that a wedge of air is formed. The plates are illuminated by perpendicularly incident light of wavelength 595 nm, and 18 interference fringes per centimeterlength of wedge appear. What is the angle of the wedge?
2. Homework Equations
x/y = L/d (similar triangles)
2y = (m + 1/2) * lambda
Tan theta = (y / x)
3. The Attempt at a Solution
calculating x' from x(m+1)  x(m), I get x'=(L/d) * (lambda/2) . the change in x, x', I think is the space between the fringes. but whether this is 1/ (18/(10^(2))) or 18/(10^(2)) I'm not sure. The latter is way too big, and resulted in an incorrect answer. The former is ultimately 1/1800, which seems intuitively right.
so 1/1800 = (L/d) * (lambda/2).
L/d = 2/(1800*lambda)
d/L = (1800*lambda)/2
theta = Arctan (d/L) =Arctan ((1800*lambda)/2)
does this look right? I haven't calculated or submitted this answer, as i wanted to wait and think it over before wasting any more of my last 3 chances to get it right.
Thanks for any tips or suggestions.
,Yroyathon
1. Homework Statement
Two rectangular pieces of glass (see attached image, I painstakingly made it with a very fussy/crashey program) are laid on top of one another on a plane surface. A thin strip of paper is inserted between them at one end, so that a wedge of air is formed. The plates are illuminated by perpendicularly incident light of wavelength 595 nm, and 18 interference fringes per centimeterlength of wedge appear. What is the angle of the wedge?
2. Homework Equations
x/y = L/d (similar triangles)
2y = (m + 1/2) * lambda
Tan theta = (y / x)
3. The Attempt at a Solution
calculating x' from x(m+1)  x(m), I get x'=(L/d) * (lambda/2) . the change in x, x', I think is the space between the fringes. but whether this is 1/ (18/(10^(2))) or 18/(10^(2)) I'm not sure. The latter is way too big, and resulted in an incorrect answer. The former is ultimately 1/1800, which seems intuitively right.
so 1/1800 = (L/d) * (lambda/2).
L/d = 2/(1800*lambda)
d/L = (1800*lambda)/2
theta = Arctan (d/L) =Arctan ((1800*lambda)/2)
does this look right? I haven't calculated or submitted this answer, as i wanted to wait and think it over before wasting any more of my last 3 chances to get it right.
Thanks for any tips or suggestions.
,Yroyathon
Attachments

1.2 KB Views: 874