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## Homework Statement

The interference pattern in this image:

http://session.masteringphysics.com/problemAsset/1074248/3/22.P45.jpg

is seen on a screen 1.0m behind an 950 lines/mm diffraction grating.

What is the wavelength of the light? (expressed in nanometers to 2 sig figs)

## Homework Equations

I know that the equation relating the variables is: d sin(theta)=m(lambda) where theta is the angle from the center maximum to the mth maxima. d being the distance between slits in the grating.

And using the small angle approximation I think you can replace sin(theta) with y/L where y is the distance between the central maximum and the mth one and L is the distance of the screen from the grating

## The Attempt at a Solution

I tried plugging the variables into the equation but I can't seem to get the right answer.

ie:

d(y/L)=m(lambda)

(1/950000)(.436/1)=1lambda

lambda=460nm which is wrong

What am I doing wrong?