- #1

pondzo

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## Homework Statement

Visible light passes through a diffraction grating that has 900 slits per centimeter, and the interference pattern is observed on a screen that is 2.58m from the grating. In the first-order spectrum, maxima for two different wavelengths are separated on the screen by 3.16 mm . What is the difference between these wavelengths?

## Homework Equations

d*sinΘ=mλ

## The Attempt at a Solution

d = 1/90000 = 1.111*10

^{-5}

d*sin(Θ

_{1})=λ

_{1}and d*sin(Θ

_{2})=λ

_{2}

using subtraction d*ΔsinΘ=Δλ (and using small angle approx d*ΔΘ=Δλ)

But I am not sure how to find ΔΘ (or how even to visualize ΔΘ)

thanks in advance.