Higher unit 2 – solutions to practice NAB.

Here are my solutions to the practice NAB for Higher unit 2.

Check your own answers carefully.  Did you;

  • mix up the equation for charged particles with those for capacitors?
  • remember to calculate the period of an ac signal in seconds?
  • make the correct substitutions for V1 and V2 in the differential amplifier question?
  • use “it” instead of nouns in your explanations?

AH Physics: wave-particle duality

We’ve been looking at wave-particle duality this week.

Here are 2 videos. The first is about electron diffraction (G. Thomson’s experiment) and De Broglie’s equation, while the second looks at the Davisson-Germer experiment.

Following on from our discussion of the Davisson-Germer experiment, I found a copy of Davisson’s Nobel Lecture online.  You can read it using the download link below.  You should be able to follow Davisson’s lecture as it ties in nicely with the modern physics element of the AH course.

Using Excel for your LO3 and Investigation

We’ll spend the next two lessons in the library learning how to use Excel.  Download the instructions using the link below.  If you have your own LO3 data, feel free to work with those values instead of the numbers I have provided.

By the end of this activity you will be able to;

  • manipulate raw data using formulae in cells
  • plot a graph of your results
  • add error bars to your graph
  • add a line of best fit
  • calculate the gradient and y-axis intercept of your line

AH Outcome 3 diagrams

Here are the diagrams you will need for your LO3 report.  Cick on each link and then save the large image that opens up.  You can rezise them once they have been imported into your report.

turntable

stand

radian sector

turntable and stand

Later this week, we’ll look at how you can use a spreadsheet to process the data you obtained.

lasers are cool!

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.

Screen shot 2013-04-18 at 19.26.22

 

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 🙁