Question

the plain transmission grating has 6000 slits/cm find the angular separation between first and third order of the spectrum for a wavelength of 50 nm​

Answer 1

Explanation:

Solution

We know that the first maximum (next to central maximum) occurs at y=λDd

Giventλˆ1=480nm

λ2=600nm

D=150cm=1.5mandd=0.25mm=0.25xx10^-3mso,y_1=(Dlamda_1)/d=((1.5)xx480xx10^-9)/(0.25xx10^-3)=2.88mmy_2=((1.5)xx600xx10^-9)/(0.25xx10^-3)sotheseparationbetweenthesetwobright∈≥sisgivenby:. Separation =y2−y1

`=3.60-2.88=0.72mm.