How Does Monochromatic Light Create a Bright Fringe in a Double Slit Experiment?

[oceanflavored]

Homework Statement

When monochromatic light passes through a double slit, a bright fringe is formed due to a path difference of
A) 1/4 "wavelength symbol"
B) 1/2 "wavelength symbol"
C) 3/4 "wavelength symbol"
D) 7/8 "wavelength symbol"
E) 1 "wavelength symbol"

please help by starting me off.
gracias :)

 

[cristo]

You need to make at least some effort. What have you studied in class on this topic?

 

[konthelion]

Start with the definitions(what do monochromatic and slit imply?) and equations to solve this problem. Also, the wavelength symbol is the greek symbol lambda.

 

[spideyunlimit]

for maxima (bright fringe)
lambda / d = x/L
where lambda is wavelength, d is distance between slits, x is distance of bright fringe, L is distance of screen from slits.

lamda = xd/L
answer is E) 1 lambda

 

[spideyunlimit]

for bright fringe, path diff is n*lambda
for dark band, it is (2n - 1)*lambda/2

 

[oceanflavored]

You need to make at least some effort. What have you studied in class on this topic?

this is a question that was in my REA SAT II physics book. we never studied this in my physics class a year ago. and there's no mention of it in my REA book. or other study books i have.

 

[oceanflavored]

for maxima (bright fringe)
lambda / d = x/L
where lambda is wavelength, d is distance between slits, x is distance of bright fringe, L is distance of screen from slits.

lamda = xd/L
answer is E) 1 lambda

that's what the book says the answer is.
but, I'm still really confused.
so the fact it's a double slit doesn't matter??
and that we don't know x and L?