# Determining wavelength of double slit experiment

## Homework Statement

If i have the intensity pattern of a double slit experiment and aim to find the wavelength of the monochromatic light incident on the slits with the following information,
- width of each slit
- distance to the screen
- intensity pattern (displacement Vs intensity)

## Homework Equations

for double slit (bright fringes):
sin $$\theta$$ = $$\frac{m \lambda}{d}$$

where m is the order of the bright fringe, d is the slit separation

for single slit (dark fringes):
sin $$\theta$$ = $$\frac{m \lambda}{a}$$

where m is the order of the dark fringe, a is the slit width

## The Attempt at a Solution

Since the double slit intensity pattern is modulated by the single slit intensity pattern is it possible to use the single slit equation and let a = the slit width?
Since for the double slit equation i have an unknown $$\lambda$$ and unknown d (slit separation).

any help would be greatly appreciated.
Thanks,