This text is meant to accompany class discussions. It is not everything there is to know about uniform circular motion. It is meant as a  prep for class. More detailed notes and examples are given in the class notes, presentations, and demonstrations (click here.)

 

Physicists and engineers have come up with a collection of symbols to represent the pieces of the electron gun. Any collection of symbols used to describe and electrical circuit is called a schematic diagram. Below are the symbols that are used in this electrostatics unit.

Below is the schematic diagram for the parallel plates attached to a 9 volt battery.

 

From the previous page the work done in traveling across these plates is found from W=qV. Ignore the sign of the charged particle. The calculated work is in the units of Joules. Physicists have created a special unit that is used to describe small amounts of energy. Take the number of Joules and divide it by the charge of an electron. This will give the unit called an "electron Volt." This is very small unit of energy. It is abbreviated with the letters "eV."

1 eV = 1.60 x 10-19 J

 
Application of "eV"

A particle with a net charge of 3 electrons travels across two plates separated by 5 cm and connected to a 100 Volt power source.The particle is traveling towards a positively charged plate. How much work is done in moving the particle between the plates.

The video below shows the solution. It can be found on YouTube at http://www.youtube.com/watch?v=AVKjMFwG_6k .

 

by Tony Wayne ...(If you are a teacher, please feel free to use these resources in your teaching.)