PHYSICS · Multi-part · Fermi University Physics · Optics & Photonics · Atomic, Molecular & Optical Physics · One-electron atoms and the origins of atomic structure
Reading the Spectrum, Ch Lines, series and the term diagram: what a spectrometer measures
Problem
A student's grating has 300 grooves per millimetre, illuminated over 20mm, and is used in first order to look at Hα near 656.46nm (vacuum) from a lamp holding a mixture of hydrogen and deuterium. The deuterium line sits 0.18nm to the short-wavelength side of the hydrogen line.
((a)) Find the resolving power mN and the smallest wavelength difference Δλ the grating can separate at this wavelength.
((b)) Decide whether the grating shows the two isotopes' lines separately, and by what factor the shift exceeds or falls short of Δλ.