Lorentz Force (Crookes Tube)
This setup demonstrates the force of a magnetic field on moving electric charges. The Crookes tube creates a beam of electrons that is visible because of an inert gas in the tube. When a magnet is brought near the tube, the beam deflects from the magnetic force.
* Equipment seen in the video may vary from equipment used in ND Demonstrations. See information and images below for ND equipment and setup.
Setup:
Setup the apparatus as shown in the photo. Setup the support rod on the lab table and attach the support platform to it (Note: If using a ring stand, consider securing it to the table with duct table or a c-clamp as the setup can be wobbly while being moved). Using the clamps, secure the Crookes Tube onto the support platform. Using two black banana cables, connect the " H " terminals on the Crookes Tube to the yellow AC jacks on the power supply (orientation does not matter). Connect the red " P " terminal on the Crookes Tube to the red High Voltage jack on the power supply. Using the other black banana cable, connect the black " K " terminal on the Crookes Tube to the black " + 500 V " terminal on the power supply.
Ensure that the apparatus is properly setup before turning it on. Turn the power supply knob down to ensure that the equipment starts at 0 V. Turn off the lights in the room.
Turn on the power supply. Set DC to 300V and AC to 6V using the power supply. It may take a moment for a blue-green beam to appear in the tube. Bring the magnet near the tube to show the deflection.
Notes:
CAUTION: High Voltage. Ensure that equipment is setup properly before use!
May need to be performed in a darkened room in order to see the electron beam.
Courses Used In:
PHY 10320
PHY 20435
PHY 30220
Discussion and Polling Questions:
Coming Soon
Equipment Needed:
Pasco SF-9585A High Voltage Power Supply
Nakamura Crookes Tube
Support Rod or Ring Stand
Support Platform
2 Clamps
1 Red Banana Cable
3 Black Banana Cables
Bar Magnet
