User:Brian P. Josey/Notebook/Junior Lab/2010/11/08: Difference between revisions
(→Set-up) |
|||
| Line 31: | Line 31: | ||
Here is where you need to have them in the set up: | Here is where you need to have them in the set up: | ||
* ''' | * '''ammeter''' -connected in series with the Helmholtz coil to measure the current going into the coils, | ||
* ''' | * '''voltmeter''' -connected in parallel with to ensure the voltage on the heater does not exceed 6.3 V, | ||
* '''voltmeter''' -connected in parallel to the electrode to measure the voltage at which the electrons are fired at. | |||
==Procedure== | ==Procedure== | ||
Revision as of 11:41, 14 November 2010
 Project name
|
<html><img src="/images/9/94/Report.png" border="0" /></html> Main project page <html><img src="/images/c/c3/Resultset_previous.png" border="0" /></html>Previous entry<html> </html>Next entry<html><img src="/images/5/5c/Resultset_next.png" border="0" /></html> |
e/m RatioThis week, my partner, Kirstin, and I did the e/m ratio experiment. This experiment it used to determine the ratio of the charge of an electron to its mass. Combined with the Millikan oil drop experiment, two fundamental physical quantities can be determined, the mass and the charge of the electron. This quantities are significant in that they are very useful in quantum mechanics, and more importantly, the charge of the electron is the fundamental charge and the smallest amount of charge that can exist on its own. (Some other subatomic particles have fractional charge, but they cannot exist on their own.) Historically, this experiment was first conducted by J. J. Thomson in 1897 using cathode ray tubes. This experiment, however, is a little more updated and has a different approach than the original groundbreaking experiment. In place of the cathode tubes, we have glass tube full of a very dilute helium gas. This tube is surrounded by a Helmholtz coil that can supply a nearly uniform magnetic field throughout the whole tube. In this tube, we will release electrons from a heater plate, focus them into a nearly coherent beam, and apply a varying magnetic field. This varying magnetic field will change the trajectory of the electrons, which emit light from the collisions with the helium, so that it forms a complete circle. We then measured the dimensions of the circular path, and the voltages used to free the electrons to determine the ratio, e/m. Set-upEquipment:
Connections:
MultimeterHere is where you need to have them in the set up:
ProcedureAfter setting up the experimental apparatus, we turned on the heater powering the electron heater to allow it to warm up. We then increased. | |
