Entries by Neil Parker

Massive Meets Massless: Compton Scattering Revisited

Introduction In a previous article entitled “Alternate Approach to 2D Collisions” we analysed collisions between a moving and stationary object by defining the co-ordinate axes as being respectively parallel and perpendicular to the post collision direction of motion of the stationary object. In this article we will be adopting the same approach to analyse the…

An Alternate Approach to Solving 2 Dimensional Elastic Collisions

Introduction This article follows on from the previous on an alternate approach to solving collision problems. In that article we determined the equal and opposite collision impulse to have magnitude ##\mu \Delta v## for perfectly inelastic collisions, ##\mu(1+e) \Delta v## for semi-elastic collisions and ##2\mu \Delta v## for elastic collisions which will be the focus…

An Introduction to the Generation of Mass from Energy

Introduction This article is essentially an addition to the previous one on (mainly) inelastic collisions to include the particular case of inelastic relativistic collisions. Reasons for writing a separate article are firstly that this author is not particularly well qualified to write on the topic and so may well need to request the careful scrutiny…

An Alternative Approach to Solving Collision Problems

Introduction Collisions are very much a stock item in any school physics curriculum and students are generally taught about the use of the principles of conservation of momentum and energy for solving simple collision problems in one dimension. In this article we will be examining a very common type of collision problem: the inelastic or…

Ionization Energy of Atomic Hydrogen

Introduction In previous articles relating to various transition energies in Hydrogen, Helium and Deuterium we have employed the following formula for electron energy given a particular primary quantum number n: $$ E_{n}=\mu c^2\sqrt{1-\frac{Z^2\alpha^2}{n^2}} $$ where ## \alpha ## is the fine structure constant and ## \mu ## the reduced electron mass for a single electron…

Revisiting The Deuterium Lyman Alpha Line Experiment

Introduction In this article we will be revisiting a somewhat understudied (and seemingly unrepeated) experiment to measure the Deuterium Lyman Alpha line at approximately 121.5 nm.  The experiment was carried out in the 1950s  in the wake of the Lamb-Retherford experiment (1947) which established the tiny energy shift (Lamb shift) between the Hydrogen (and Deuterium)…

Understanding Bohr’s Helium Lines

Introduction In a previous article “Calculating the Balmer Alpha Line” we mentioned how accurate predictions of the spectral lines of singly ionized Helium were of considerable importance in persuading the scientific community that Danish physicist Niels Bohr was on the right track in respect of his ground breaking atomic model first published in 1913. In…

Calculating the Balmer Alpha Line: Atomic Hydrogen

Introduction Most readers acquainted with the hydrogen spectrum  will be familiar with the set of lines in the visible spectrum representing transitions of electrons from energy levels 3,4,5 and 6 (H alpha, beta, gamma and delta respectively)  of atomic hydrogen to energy level 2 – the Balmer series lines. The picture below shows 3 of these…