`d=2 mm, D=2.5 m, x=1 mm`
For present wavelengths, use condition of maxima
`y=(nDlambda)d`
`1xx10^(-3)=(nxx2.5lambda)/(2xx10^(-3))`
`lambda=2/2.5xx10^(-6)/n`
`=(0.8xx10^(-6))/nm`
`=800/n nm`
`n=1, lambda=800 nm`
`n=2, lambda=400 nm`
`n=3, lambda=800/3~=267 nm`
`n=4, lambda=200 nm`
Wavelength in infrared region`=800 nm`
Wavelength in ultraviolet region `=200 nm, 267 nm`
Wavelength in visible region `=400 nm`