E/M Experiment

SETUP: Start by setting up the apparatus as pictured below with the low voltage supply on the left of the apparatus and the high voltage on the right. *DO NOT TURN SUPPLIES ON UNTIL INSTRUCTED* 

Then we will hook up the wires as pictured.

Power Supply Settings and Startup: With the supplies still off we will turn the nobs marked by yellow 1, 2 and 3 all the way down (counter-clockwise)

Set knob yellow 5 to 5 or 6 volts AC. 5 is good for most, only switch to 6 if otherwise instructed.

Then switch on both machines and make sure that the button at yellow 4 is set to 500V, not 50V.

After letting the system warm up for a minute we will turn up knob yellow 3 to about 120V

*note* Some setups will use the supply pictured as the Low Voltage power supply (left side of the apparatus). Also note that the Voltage and Current knobs are opposite of each other from the other low voltage power supply and all 4 knobs should be turned down before powering on the device.

Generate Magnetic Field: We turn the current knob on the low voltage power supply all the way up and then slowly increase the voltage knob until we get a decently sized circle in the bulb. It should not take a lot, around 1 amp.

If you are not getting a good circle of light check the current knob on the E/M apparatus itself. It should be located next to plug points E and F on the first picture.

Gathering Data: Finally we should get something like pictured above. If you notice there is a a mirrored ruler in the background. You will want to bend or kneel down until you are eye level with that. Then close one eye and move your head left or right until the light (marked by 1 in the image above) and the reflection of the light (marked by 2) are in line and then you will read the measurement on the ruler.

Take the Average: You will want to repeat that procedure for both sides of the circle and take the average for a more accurate reading.

*note* If you can’t read the mirrored ruler you may want to use some external use of light (phone, flashlight, etc) to highlight it so it is easier to read, but you need to be careful not  to make it to bright to see the glow and the reflection.