Here are the solutions to the practice NAB for unit 3. How did you get on?
E-Book PDF: Open in New Window | Download
with mr mackenzie
Here are the solutions to the practice NAB for unit 3. How did you get on?
E-Book PDF: Open in New Window | Download
Here is a practice NAB for unit 3. Answers will follow shortly.
E-Book PDF: Open in New Window | Download
The first laser was demonstrated in 1960 by Theodore Maiman and his research group at Hughes† in California. Here is a good background article on the first laser, its inventor and the role that Einstein played in developing the theory of stimulated emission.
The principle of laser operation is outlined in this description of Maiman’s laser, which used a rod of polished ruby inside a spiral flashtube.
My favourite James Bond film, Goldfinger, has a scene where Sean Connery (the best 007 imho) is strapped to a table under a huge red laser. It should have been a saw but the invention of the laser, just 4 years earlier, was a gift for the writers. This scene helped the film win the best effects Oscar in 1965 and, more importantly, gave us the ultimate Bond quote:
Bond: Do you expect me to talk?
Goldfinger: No, Mr. Bond, I expect you to die.
Everyone should watch the laser scene.
Bonus points if you can tell me about the bad physics in that clip…
You can try running a laser for yourself. Click on the picture below to load a simulator. You’ll need Java on your computer to run the simulation.
Try changing lamp (pump) irradiance and mirror reflectivity on the single atom version before moving on to the multiple atom tab.
There are some pdf notes on lasers attached to the end of this post.
† Disclaimer: I used to work for Hughes before I trained as a physics teacher – the Glenrothes branch, not California 🙁
E-Book PDF: Open in New Window | Download
We looked at line spectra with a spectrometer before the holidays and this week we considered how these different colours of light are produced.
Here is a website that lets you choose the energy of a photon and see whether or not it causes a change in the energy of an electron inside the hydrogen atom.
You can read more about line spectra and where they come from here and here.
The visible line spectrum of the Hydrogen atom is explained in the following short film. Click on the image below to start the clip.
I’ve attached a pdf file with further notes on line spectra and the absorption/emission of photons.
E-Book PDF: Open in New Window | Download
Sorry if you’ve encountered a maintenance screen this week. My site was hacked and I had to reinstall everything from scratch. Most things should work but please leave a comment if something is broken and I’ll get it fixed as soon as I can.