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**[SOLVED] Easy question on diffraction of light please help!**

## Homework Statement

Wavelengths are; 1 - 520nm

Wavelength 2 - 520.8nm

Diffraction grating - 400 lines per mm

How many orders will the lines be seen in?

## Homework Equations

N = dsin0/lamda

## The Attempt at a Solution

d = 1/4 X 10^5 = 25 X10^-7m

25 X 10^-7 / 520 X 10^-9 = 4.8

So is the answer 4??? for the first wavelength (520nm)