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## Homework Statement

Two slits are 0.158mm apart. A mixture of red light (wavelength = 665nm) and yellow-green light (wavelength = 565nm) fall onto the slits. A screen is located 2.2m away. Find the distance between the third-order red fringe and the third-order yellow-green fringe.

## Homework Equations

Since they ask for colored fringes, and not dark ones, it must be constructive interference.

x/L = (m*λ/ d)

x = 0.000158m

L = 2.2m

m = 3 (third order fringe)

λ of red = 6.65E-7m

λ of yellow-green = 5.65E-7m

## The Attempt at a Solution

I did the equation twice, once for each wavelength.

For red I got x as 2.7E-2m, and for yellow-green i got x as 2.36E-2m.

The difference between these 2 values is 0.0034mm or 3.4mm.

The answer however, is supposed to be 28mm. . .

How was I supposed to do this?