Revisiting Fizeaus Observations: Spectral study of Na source using Newtons rings

TL;DR

This study enhances the classical Newton's rings experiment by enabling simultaneous observation in reflection and transmission, allowing precise spectral analysis of sodium doublet through fringe contrast variation.

Contribution

It introduces a modified setup with a movable glass plate to observe and analyze sodium doublet spectral features using Newton's rings.

Findings

Simultaneous reflection and transmission fringe observation.

Ability to determine sodium doublet separation.

Enhanced spectral analysis technique.

Abstract

Conventional Newtons rings is generally used in undergraduate laboratory to determine the average wavelength of Na doublet. A minor modification of this setup enables us to view simultaneously Newtons rings both in reflected as well as transmitted light. A movable glass plate with respect to the plano-convex lens allows us to observe the variation of contrast/visibility of these fringes and thus allows us to determine the separation of the yellow doublet.