- #1

TheKShaugh

- 22

- 0

## Homework Statement

A grating has a line density of 1010

*cm*−1, and a screen perpendicular to the ray that makes the central peak of the diffraction pattern is 2.5

*m*from the grating. If light of two wavelengths, 590

*nm*and 680

*nm*, passes through the grating, what is the separation on the (flat) screen between the second-order maxima for the two wavelengths?

## Homework Equations

[tex]dsin\theta = m \lambda[/tex]

## The Attempt at a Solution

I thought I would find the angular distance to the second order maxima covered by each wavelength:

[tex]\theta = arcsin(\frac{2 \lambda}{d})[/tex] where d is [tex]\frac{1}{1010}\times 10^{-2}[/tex]

Then I would take the difference, and plug it into the equation [tex]sin\theta = \frac{y}{L}[/tex] and solve for y. This gives me the wrong answer but I don't see why this wouldn't work. Can anyone see my mistake?

Thanks!