Hey guys, I came across this physics question in my studies and am not sure what the answer is.
A spectral line of known wavelength (5.792*10E-7) emitted from a mercury vapour lamp is used to determine the spacing between the lines ruled on a plane diffraction grating. When the light is incident normallyhon the grating, the third-order spectrum, measured using a spectrometer, occurs at an angle of 60 degrees and 19 minutes to the normal. Calculate the grating spacing.
This question i can do but the next part i am not sure of:
Why is the value obtained using the third-order spectrum likely to be more accurate than if the first-order were used?
A spectral line of known wavelength (5.792*10E-7) emitted from a mercury vapour lamp is used to determine the spacing between the lines ruled on a plane diffraction grating. When the light is incident normallyhon the grating, the third-order spectrum, measured using a spectrometer, occurs at an angle of 60 degrees and 19 minutes to the normal. Calculate the grating spacing.
This question i can do but the next part i am not sure of:
Why is the value obtained using the third-order spectrum likely to be more accurate than if the first-order were used?